EVERYDAY   HEALTH 
SERIES 


BOOK  TWO 


KEEPING  THE  BODY  IN  HEALTH 


IC-NRLF 


V 


VL- 


O'SHEA  &    KELLOGG 


GIFT   OF 


THE  EVERYDAY  HEALTH  SERIES 

BOOK  TWO:  KEEPING  THE  BODY  IN  HEALTH 


THE    EVERYDAY   HEALTH    SERIES 


BOOK  ONE:    BUILDING    HEALTH    HABITS 

BOOK    TWO:      KEEPING    THE     BODY    IN 
HEALTH 


THE  EVERYDAY  HEALTH  SERIES 


BOOK  Two 


KEEPING  THE    BODY   IN    HEALTH 


BY 
M.  V.  O'SHEA 

PROFESSOR  OF  EDUCATION,  THE  UNIVERSITY  OF  WISCONSIN 
AUTHOR  OF  "MENTAL  DEVELOPMENT  AND  EDUCATION,"   ETC.,   ETC. 


AND 

J.  H.  KELLOGG 

SUPERINTENDENT  OF  THE  BATTLE  CREEK  SANITARIUM 
AUTHOR  OF  "MAN,  THE  MASTERPIECE,"   ETC.,  ETC. 


Ntto  garfe 
THE    MACMILLAN    COMPANY 

1924 

All  rights  reserved 


PRINTED    IN    THE    UNITED    STATES    OF    AMERICA 


Os  7 


COPYRIGHT,  1915,  1921, 
BY  THE  MACMILLAN  COMPANY. 


Set  up  and  electrotyped.     Published  December,  1921.    Reprinted 
October,  1924. 


Qtft 

DfcPT* 


Norboooti 

J.  8.  Cushine  Co.  —  Berwick  &  Smith  Co. 
Norwood,  Mass.,  U.S.A. 


INTRODUCTION 

IT  is  the  aim  in  The  Everyday  Health  Series  to  present  in  an 
attractive  form  for  pupils  in  the  elementary  school  the  latest  and 
most  accurate  knowledge  relating  to  physiology  and  especially  to 
the  hygiene  of  daily  life.  The  constant  effort  of  the  authors  has 
been  to  make  scientific  knowledge  so  simple,  so  concrete,  and 
so  inviting  that  pupils  can  hardly  fail  to  take  an  interest  in 
the  problems  of  preserving  health  for  the  purpose  of  making 
the  most  of  life. 

The  aim  has  been  kept  in  view  of  awakening  in  the  young  a 
normal  desire  to  live  in  such  a  manner  as  to  develop  strength 
and  preserve  health,  because  in  this  way  one  may  best  achieve 
success  in  securing  the  things  which  he  desires,  and  in  avoiding 
the  disabilities  and  pains  which  otherwise  are  likely  to  occupy 
a  considerable  part  of  his  life. 

Comparatively  little  attention  is  given  to  anatomy,  and  only 
sufficient  physiology  is  presented  to  constitute  a  basis  for  the 
facts  of  health  which  are  discussed.  Very  extensive  use  is  made 
of  photographs  and  diagrams  illustrating  everyday  life  in  the 
city  and  in  the  country.  There  is  at  least  one  interesting  and 
practical  original  exercise  suggested  for  every  principle  of  health 
presented  in  each  lesson.  In  order  further  to  assist  the  teacher 
and  the  pupil,  a  list  of  questions,  fully  covering  the  text,  has  been 
given  at  the  end  of  each  chapter. 


PREFACE 

EVERY  one  would  like  to  have  a  vigorous  body,  free  from 
aches  and  pains  and  fit  for  any  kind  of  work  or  pleasure.  How 
can  one  maintain  his  body  in  this  condition  ?  This  book  is 
designed  to  answer  this  question.  It  shows  how  habits  of 
living  affect  the  strength,  endurance,  stature,  symmetry,  and 
poise  of  the  body.  Attention  is  given  to  the  problem  of  how 
to  keep  the  vital  organs  in  good  working  order  so  that  they 
can  destroy  the  enemies  of  the  body  and  furnish  energy  for 
all  the  work  it  has  to  do.  A  person  cannot  keep  in  good  physical 
condition  without  giving  consideration  to  what  he  eats  and 
drinks,  and  also  to  the  manner  in  which  he  performs  these 
two  acts;  in  this  work  these  matters  are  considered  in  detail. 
Many  people  deliberately  handicap  themselves  in  the  race  of 
life,  though  they  may  not  be  aware  of  what  they  are  really 
doing.  This  book  goes  into  all  phases  of  bodily  care  in  a  simple, 
concrete  way.  Topics  concerning  elimination  of  poisons  from 
the  system,  helping  the  body  to  repair  itself  when  it  becomes 
worn,  and  fortifying  it  so  that  it  can  defend  itself  against 
attacks  from  without  as  well  as  from  within,  are  given  a  prom- 
inent place.  One  cannot  have  the  kind  of  body  he  desires, 
nor  get  the  most  out  of  life,  unless  the  mind  as  governor  of  the 
body  is  properly  trained  and  kept  in  a  condition  of  health  and 
poise ;  this  subject  is  also  treated  herein. 

The  authors  of  The  Everyday  Health  Series  believe  that  one 
of  the  best  ways  to  impress  facts  of  health  is  to  present  them 
to  the  eye  in  photographs  and  drawings.  This  book  is  fully 
illustrated  with  pictures  made  especially  for  this  purpose.  As 


viii  PREFACE 

an  aid  to  teacher  and  pupils,  each  topic  discussed  is  indicated  in 
a  marginal  heading.  The  authors  further  believe  that  in  order  to 
get  the  most  out  of  their  study  of  hygiene,  pupils  should  apply 
principles  of  health  in  their  everyday  life,  and  to  facilitate  this 
practice  a  list  of  problems  relating  to  health  is  given  at  the  end 
of  each  chapter.  Lastly,  a  detailed  list  of  review  questions  is 
added  to  each  chapter.  A  glossary  and  an  index  are  given  at  the 
close  of  the  book. 


CONTENTS 

CHAPTER  PAGE 

I.    LIVING  WONDERS  or  THE  BODY i 

II.  THE  MAINTENANCE  OF  THE  BODY       .        .        .        .        .11 

III.  How  FOOD  BECOMES  LIVING  TISSUE          .  23 

IV.  EATING  FOR  HEALTH  AND  PLEASURE          .        .  44 
V.  GETTING  PURE  FOOD  AND  KEEPING  IT  PURE    .                .      56 

VI.  THE  BLOOD          .......                       71 

VII.  PURE  BLOOD  AND  A  SOUND  HEART     ...                      92 

VIII.    THE  BREATH  OF  LIFE 103 

IX.    How  THE  BODY  CLEANSES  ITSELF 126 

X.  How  THE  TEMPERATURE  OF  THE  BODY  Is  REGULATED     .     136 

XL    THE  FRAMEWORK  OF  THE  BODY 149 

XII.  THE  BODY  IN  MOTION         .......     167 

XIII.  HEALTH  AND  SYMMETRY       .        .  .        .        .        .177 

XIV.  FEELING  AND  THINKING 190 

XV.  GATEWAYS  OF  THE  MIND  —  SIGHT      .        .        .        .             207 

XVI.  GATEWAYS  OF  THE  MIND  —  HEARING         .        .        .        .225 

XVII.  GATEWAYS  OF  THE  MIND  —  SMELL,  TOUCH,  AND  TASTE    .     232 

XVIII.  Two  ENEMIES  OF  THE  BODY  —  ALCOHOL  AND  TOBACCO    .     240 

XIX.  OTHER  ENEMIES  OF  THE  BODY  —  DISEASE  GERMS     .        .     248 

XX.    "CATCHING"  DISEASES 260 

XXI.     HEALTH  CRUSADERS 272 

APPENDIX  —  TABLES  OF  COMPOSITION  OF  FOODS        .        .        .        .289 

GLOSSARY     .  293 

INDEX 305 


KEEPING  THE  BODY  IN 
HEALTH 

CHAPTER  I 

LIVING  WONDERS  OF  THE  BODY 

IF  you  look  at  a  brick  house  from  a  distance,  you  can  see  only 
its  general  form  and  outline.  As  you  come  closer  to  it,  you  can 
see  distinctly  the  bricks  of  which  the  house  is  made. 

Like  the  house,  the  human  body  is  composed  of  many  small 
parts.  These  tiny  living  bricks  of  which  the  body  is  built  are 
called  cells.  These  cells  are  so  small  that  they  cannot  be  seen 
by  the  naked  eye.  When  we  examine  a  piece  of  flesh  under 
a  microscope,  we  see  that  it  is  made  up  of 
separate,  distinct,  perfectly  formed,  and 
exceedingly  small  parts.  Though  these 
differ  greatly  in  shape,  color,  and  use,  they 
are  all  known  as  cells.  All  living  things, 
both  vegetable  and  animal,  are  composed 

of  similar  cells.  THE    AM<EBA   STRETCHES 

mi  .  i  i    •    i  ITSELF  OUT  IN  THE  DI- 

There  are  some  minute  animals  which  RECTION  IT  WISHES  TO 
consist  of  just  a  single  cell.  The  amoeba,  G0> AND  DRAWS ITSELF 

.  ALONG  LIKE  A  WORM. 

found  in  ditch  water  and  stagnant  pools,  is 
an  example  of  a  single-celled  animal.     Seen  under  the  micro- 
scope, this  one-celled  animal  looks  much  like  a  minute  drop  of 
jelly.     It  has  no  mouth,  yet  it  can  eat.     It  spreads  itself  over 
or  around  a  particle  of  food  and  absorbs  it,  just  as  water  flowing 


KEEPING  THE  BODY  IN  HEALTH 


down  a  pane  of  glass  may  pick  up  particles  of  dust.  It  has  no 
limbs,  yet  it  moves  easily  and  rapidly  from  place  to  place. 
It  stretches  itself  out  in  the  direction  it  wishes  to  travel  and 
draws  itself  along  from  place  to  place,  like 
a  worm,  continually  changing  its  form.  It 
eats,  breathes,  moves,  and  rests.  This 
simple  and  fragile  little  cell  is  so  minute 
that  it  takes  850  amoebae  arranged  side  by 
side  to  make  a  row  an  inch  long;  and  100 
can  swim  about  in  a  drop  of  water  which 
would  hang  on  the  point  of  a  pin. 

Whence  do   the  tiny  cells  of   which  all 

Every  cell 

comes   from   another  cell.      How  are   cells 
formed  ?     They  are  formed  by  the  dividing 


EVERY  CELL  HAS  A  NU- 

CLEUS —  WHICH  MAY  BE 
SAID   TO    BE   ITS   HEART 

-  AND  SURROUNDING    living  things.  are  formed  come? 


MATERIAL  WHICH  FCR- 
NISHES  IT  NUTRITION. 
THERE  ARE  OTHER 
PARTS  TO  THE  CELL,  BUT 

WE  DO  NOT  NEED  TO    of  each  cell  .into  two  new  cells,  as  you  see 

and 


STUDY     THEM     AT    THIS 


pcture     Qn    page 

of  division  goes  on  until  millions  of  cells 
are  formed  in  a  short  time. 

When  you  examine  the  jelly  like  mass  of  the  amoeba  under 
the  microscope,  you  see  in  it  a  dense,  grayish  portion,  which  is 
How  the  ^e  nucleus  of  the  cell.  When  the  cell  is  preparing  for 
cells  are  division,  the  nucleus  divides  and  part  of  it  goes  to 
formed  each,  end  of  the  cell.  A  wall  is  then  formed  across  the 
middle  of  the  cell,  separating  it  into  two  parts.  Each  part 
is  a  complete  new  cell,  having  its  own  nucleus.  When  a  single- 
celled  animal  divides  in  this  way,  each  of  the  new  cells  forms  a 
complete  new  animal,  which  grows  to  the  size  of  the  parent 
and  then  divides  and  makes  two  cells. 

The  bodies  of  animals  larger  than  the  amoeba,  instead  of  hav- 
ing a  single  cell,  may  be  made  up  of  millions  of  cells,  each 
one  of  which  is  a  real  living  being  much  like  the  amoeba.  Each 


LIVING  WONDERS  OF  THE  BODY  3 

animal  body  begins  with  a  single  cell;  but  when  this  divides, 
the  cells  do  not  separate  and  live  alone,  as  in  the  case  of  the 
single-celled  animals.  They  remain  together  and  keep  on 
dividing  and  redividing  until  there  may  be  many  millions  of 
them,  all  living  together  and  working  for  the  common  good. 

The  body  may  be  compared  to  a  swarm  of  bees,  except  that 
in  the  case  of  the  bees  each  one  may  live  for  some  time  apart 
from  the  rest  if  he  chooses  to  do  so.     This  is  true  to  CeU 
a  small  extent  of  the  cells  of  which  animals  and  plants  colonies 
are  composed.     When  a  portion  is  cut  from  a  plant  orcom- 
or  animal,  its  cells  do  not  always  die  at  once.     The  munities 
legs  of  a  frog  will  twitch  and  kick  after  they  are  severed  from 


THIS  PICTURE    SHOWS  HOW  A  CELL  DIVIDES  TO  MAKE   TWO,  EACH    ONE    A    PERFECT   CELL. 

the  body.  The  heart  of  a  turtle  will  continue  to  beat  for  hours 
after  its  head  has  been  removed.  When  some  kinds  of  worms 
are  cut  in  two,  each  part  will  live  and  grow  into  a  complete  worm. 
A  flower  stem  cut  from  certain  plants  will  continue  to  live  and 
bloom  for  days  in  water.  A  branch  cut  from  certain  trees  and 
stuck  in  the  ground  may  even  grow  into  a  new  tree.  This  is 
because  each  part,  being  made  up  of  separate  living  cells,  can 
maintain  life  by  itself. 

For  this  reason  it  is  sometimes  possible  to  remove  a  portion  of 
one  animal  and  graft  it  upon  another  animal  of  the  same  kind. 
In  the  ordinary  process  of  grafting  fruit  trees,  a  bud  of  one  tree 


4  KEEPING  THE  BODY  IN  HEALTH 

is  planted  in  a  little  slit  cut  in  the  bark  of  another  tree.  When 
the  work  is  well  done,  the  bud  soon  becomes  accustomed  to  its 
new  home  and  grows  and  bears  fruit  and  leaves  like  its  parent. 

In  somewhat  the  same  manner,  surgeons  sometimes  take 
pieces  of  skin  from  one  or  -several  persons  to  graft  upon  another 
person  who  has  lost,  by  burning  or  some  other  accident,  large 
portions  of  skin.  Many  cases  have  occurred  in  which  the  severed 
part  of  a  finger  has  been  replaced  and  has  grown  on  again. 
Surgeons  often  graft  in  portions  of  bone  to  repair  diseased 
or  injured  limbs,  and  in  a  few  cases  even  kidneys  and  other 
organs  have  been  successfully  transplanted.  Organs  and  tissues 
may  be  kept  alive  for  months  after  removal  from  the  body,  and 
certain  tissues  may  even  be  made  to  continue  to  grow. 

The  human  body  may  well  be  compared  to  a  community  made 
up  of  multitudes  of  individuals.  There  are  few  if  any  idlers  in 
this  community;  all  the  cells  are  active  workers, 
human  ^n  most  communities  there  are  different  classes  of 
body  is  workers,  such  as  merchants,  blacksmiths,  chemists, 
like  a  and  bakers.  In  the  body,  likewise,  there  is  a  division 

of  labor.  Some  cells  build,  others  tear  down.  Some 
mumty 

may  be  compared  to  artists ;  and  others  —  the  cells 
which  work  to  keep  the  body  clean  and  healthy  —  to  scavengers. 
Some  make  different  kinds  of  fluids  to  be  used  in  the  body. 
There  are  cells  that  stand  as  sentinels  to  give  the  body  warning 
of  danger,  and  others  that  are  little  soldiers  who  defend  it  against 
the  enemies  of  life  and  health. 

In  the  building  of  a  house,  different  sets  of  workmen  are  em- 
ployed for  the  different  parts :  bricklayers  for  laying  the  brick 
Ceil  walls  ;  carpenters  for  the  doors  and  other  woodwork ; 

structures  plumbers  for  the  drainage  pipes  ;  and  so  on.  In  like 
or  tissues  manner,  the  little  cell  builders  form  themselves  into 
groups  for  building  up  the  different  structures  needed  in  the 


LIVING  WONDERS  OF  THE  BODY 


body.  These  different  structures  are  called  tissues.  A  large 
part  of  the  work  of  the  cells  is  to  build  and  repair  these  living 
tissues  of  which  the  body  is  composed. 

Some  of  the  cells  form  long,  white,  threadlike  fibers,  which 
are  very  tough  and  unyielding.  This  fibrous  tissue  is  needed 
to  bind  the  different  parts  of  the  body  together  and  to  make  cords 
and  protective  coverings.  There  is  also  a  yellow  elastic  tissue 
which  may  be  stretched  like  India  rubber. 

The  yellow  elastic  tissue  and  the  fibrous  tissue  together  form, 
in  all  parts  of  the  body,  a  marvelously  strong  though  elastic 


THIS  WHITE  CORD-LIKE 
TISSUE  BINDS  THE 
DIFFERENT  PARTS  OF 
THE  BODY  TOGETHER. 


THIS  YELLOW  ELASTIC  TISSUE 
ALSO  BINDS  THE  TISSUES 
TOGETHER  AND  SERVES  FOR 
BANDS,  COVERING  MEM- 
BRANES, AND  SHEATHS. 


ADIPOSE  TISSUE,  FORMED  BY 
CELLS  OF   FAT   OCCUPYING 

THE  MESHES  OF  THE  CON- 
NECTIVE TISSUE,  MAKES 
CUSHIONS  FOR  DELICATE 
ORGANS  LIKE  THE  EYE. 


mesh- work  called  connective  tissue.  This  binds  the  tissues 
together,  forms  sheaths,  membranes,  bands,  pouches,  and  cov- 
erings, and  serves  everywhere  for  purposes  of  protection  and 
support. 

The  meshes  of  the  connective  tissue  network  in  some  parts 
of  the  body  are  occupied  by  cells  composed  of  fat.     This  soft 


KEEPING  THE  BODY  IN  HEALTH 


adipose  tissue,  as  it  is  called,  rounds  out  the  form,  makes  cush- 
ions for  delicate  organs  like  the  eye,  and  serves  other  useful 
purposes. 

Other  groups  of  cells  form  what  is  called  muscular  tissue, 
and  by  this  all  sorts  of  movements  are  made.     This  tissue  is 

composed  of  minute  fi- 
bers which  shorten  and 
lengthen,  much  as  an 
earthworm  contracts  and 
extends  its  body  when  in 
motion. 

The  hardest  of  the  tis- 

THESE  CELLS  ARE  FOUND  IN  CARTILAGE  TISSUE.      RE-     SUCS    which    the    Cells    build 
MEMBER.  ALL  TISSUES  ASE  COMPOSED  OF  CELLS.  ,  i  i        j  n     j 

up  in  the  body  is  called 

bone  or  osseous  tissue.  The  bones  serve  as  supports  for  the 
body  and  as  levers  by  means  of  which  it  is  moved  about  by  the 
muscles. 

Cartilage  tissue,  which  is  usually  connected  with  the  bones,  is 
something  like  the  bone  tis- 
sue, but  softer  and  capable 
of  bending  under  pressure. 

The  most  remarkable  groups 
of  cells  found  in  living  beings 
are  in  the  nervous  tissue,  of 
which  the  brain  and  nerves 
are  composed.  These  are 
used  in  thinking  and  feeling. 

Layers  of  CUrioUS  Cells  COVer    LAYERS  OF  CELLS  LIKE  THESE  COVER  THE  EN- 

the  whole  surface  of  the  body      TIRE  SURFA^  OF  THE  BODY  AND  LINE  ALL 

J        CAVITIES.    THEY  ARE  EPITHELIAL  CELLS. 

and  line  all  its  cavities.    These 

are  called  epithelial  cells,  because  the  skin  or  covering  that  they 

help  to  form  is  called  epithelium. 


LIVING  WONDERS  OF  THE  BODY  7 

Among  the  most  interesting  of  the  many  millions  of  cells  in 
the  body  are  the  gland  cells.     The  glands  are  groups  of  cells 
which  form  peculiar  substances  for  the  carrying  on  Gland 
of  the  work  of  the  body.     There  are  many  different  cells 
kinds  of  gland  cells.     Some  sets  of  these  cells  form  saliva;  others 
make  gastric  juice;    others  are  found  in  the  liver,  making  bile. 
Millions  of  little  groups  of  cells  found  in  the  skin  make  sweat; 
others  make  fat  which  oils  the  hair  and  the  skin.     Other  gland 
cells  separate  from  the  blood  poisonous  substances  which  are 
formed  in  the  body  or  which  are  taken  in  with  the  food  or  drink. 


GLAND  CELLS 
A,  after  rest ;  B,  after  slight  activity;  C,  after  greater  activity 

In  studying  all  these  cells  and  their  work,  one  is  constantly  led 
to  marvel  at  their  alertness,  faithfulness,  industry,  and  persever- 
ance. 

The  one-celled  animal,  living  alone,  must  do  everything  for 
itself.     All  that  is  necessary  for  its  life  must  be  performed  by 
that  single  cell.     It  moves  itself  about,  gathers  its  own  food, 
eats  and  digests  it,  and  discharges  its  wastes.     In  the  community 
of  cells  that  form  the  living  body,  however,  the  work  cell  groups 
is  divided,  —  different  duties  being  assigned  to  differ-  are  called 
ent  groups  of  cells.     The  cells  doing  the  same  kind  orsans 
of  special  work  for  the  body  are  grouped  together,  and  these 
cell  groups  are  called  organs. 

All  many-celled  animals  and  plants  have  the  work  divided 


8 


KEEPING  THE  BODY  IN  HEALTH 


among  the  different  organs,  and  so  are  said  to  be  organized  and 
are  sometimes  spoken  of  as  organisms.  They  are  said  to  belong 
to  the  organic  world.  A  rock  or  a  mountain,  which  has  no 
organs,  is  said  to  belong  to  the  inorganic  world. 

As  the  wood,  brick,  stone,  and  mortar  are  combined  and  ar- 
ranged to  form  the  parts  of  a  house  and  its  furniture,  so  the  simple 

structures  or  tissues  are 
combined  and  arranged  to 
form  the  different  organs 
of  the  body.  In  the  hand, 
for  example,  we  have  bone, 
muscular,  connective,  and 
skin  tissue  combined  in  such 
a  way  as  to  form  an  organ 
suitable  for  grasping.  Some 
organs,  like  the  heart,  are 
made  chiefly  of  one  kind  of 
tissue. 

Each  organ  has  its  special 

THE   CELLS   WHEN   THEY  DIVIDE   UNITE   TO    FORM     WOrk     tO     do     for     the     bodv, 

and  the  life  and  health  of 

all  the  cells  depend  upon  its  doing  its  work  well.  The  stomach 
and  intestines  are  organs  for  digesting  the  food;  if  they  fail 
in  this  work  all  the  body  cells  starve.  The  lungs  take  in  the 
oxygen  that  the  cells  need,  and  the  kidneys  remove  poisonous 
and  waste  matters.  The  heart  pumps  the  blood  which  carries 
the  food  supply  to  every  part  of  the  body,  furnishing  all  the 
cells  with  nourishment.  The  brain  and  spinal  cord  send  out 
tiny  living  threads,  called  nerves,  which  run  throughout  the 
body,  dividing  and  subdividing  until  they  reach  every  part  of  it 
and  bring  under  their  influence  each  individual  cell,  with  the  ex- 
ception of  the  floating  cells  in  the  blood. 


LIVING  WONDERS  OF  THE  BODY  Q 

When  all  the  cells  and  organs  of  the  body  are  acting  properly, 
a  person  is  said  to  be  in  a  state  of  health.     When  anything  in- 
terferes with  the  work  of  any  of  the  organs,  so  that  Cells  ^ 
it  is  done  imperfectly  or  not  at  all,  the  person  suffers  organs  in 
discomfort  and  is  said  to  be  in  a  state  of  ill  health  or  health 
disease.     It  is  of  the  utmost  importance  that  the  vast  army  of 
little  workers  of  which  we  are  formed  should  be  kept  in  health 
and  vigor.     Anything  which  injures  them  or  hinders  their  ac- 
tivity is  dangerous  to  our  life  and  health. 

There  are  some  things  which  have  a  very  injurious  effect  upon 
organs  of  the  body.  Among  these  are  tobacco  and  alcohol.  By 
numerous  experiments  upon  animals,  and  by  examinations  made 
after  death  upon  the  bodies  of  persons  who  had  been  addicted 
to  the  use  of  alcoholic  drinks,  it  has  been  found  that  every  tissue 
of  the  body,  especially  of  the  liver  and  the  brain,  is  injured  by 
alcohol.  Alcohol  lessens  the  activity  of  the  cells  that  build  the 
body  and,  taken  in  strong  doses,  may  even  paralyze  them  com- 
pletely. This  is  one  reason  why  a  person  who  indulges  in  alco- 
holic drinks  does  not  recover  from  an  accident  so  quickly  as  one 
who  does  not  use  alcohol.  The  cells  are  hindered  in  their  work 
of  repairing  the  damage  that  has  been  done.  Many  eminent 
surgeons  have  noticed  this  fact. 

Tobacco  has  almost  as  bad  an  effect  as  alcohol  upon  the 
tissue-building  cells.  This  is  the  reason  why  the  boy  who 
begins  to  smoke  at  an  early  age  is  usually  stunted  in  his  growth 
and  puny. 

HEALTH  PROBLEMS 

1.  Suppose  you  were  talking  with  a  person  who  thought  that  stones 
were  made  up  of  cells.    What  should  you  say  to  him  to  make  it  clear  that 
cells  are  found  only  in  living  things  ? 

2.  Mention  several  communities  or  colonies  of  cells  in  the  human  body. 
What  are  these  communities  or  colonies  called? 


10  KEEPING  THE  BODY  IN  HEALTH 

3.  Have  you  ever  seen  a  tree  grafted?    How  was  the  work  done? 
Did  the  graft  live  ?    If  so,  explain  how  this  was  possible. 

4.  What  is  meant  by  saying  that  the  body  is  a  community?     Show  in 
what  way  it  resembles,  in  number  and  in  kinds  of  workers,  a  community 
like  the  one  in  which  you  live. 

5.  Tell  where  in  your  body  white  fibrous  tissue  can  be  found ;   con- 
nective tissue ;   adipose  tissue ;  osseous  tissue ;  cartilage  tissue ;  muscular 
tissue ;  nervous  tissue. 

6.  Suppose  some  one  organ  of  the  body  did  not  do  its  duty.     Would 
this  affect  the  body  as  a  whole?     Is  the  effect  the  same  in  the  community 
in  which  you  live,  when  some  person  does  not  do  his  duty? 

REVIEW  QUESTIONS 

1.  Why  can  we  not  see  the  cells  of  the  human  body  with  the  naked  eye? 

2.  If  you  should  examine  a  piece  of  flesh  under  a  microscope,  what 
would  you  see  ? 

3.  Describe  the  amoeba  as  seen  under  a  microscope. 

4.  How  are  the  cells  of  the  body  formed? 

5.  Of  what  are  the  bodies  of  large  animals  composed?    With  what  does 
the  body  of  every  animal  begin  ? 

6.  What  is  meant  by  saying  that  there  is  "division  of  labor"  in  the 
human  body? 

7.  How  are  the  tissues  of  the  body  made? 

8.  Mention  the  various  kinds  of  tissues  and  their  uses. 

9.  What  are  the  epithelial  cells?    Where  are  they  found? 

10.  What  are  the  gland  cells  and  what  are  their  uses? 

11.  What  is  the  meaning  of  organs ?    Mention  a  number  of  organs  in  the 
human  body. 

12.  What  has  been  found  regarding  the  influence  of  alcohol  upon  the 
workers  of  the  body  ?    What  organs  are  hurt  most  by  alcohol  ? 

13.  What  is  the  effect  of  tobacco  upon  the  workers  of  the  body? 


CHAPTER  II 

THE  MAINTENANCE  OF  THE  BODY 

No  large  community  of  people  remains  exactly  the  same  for 
any  length  of  time.  Constant  changes  take  place  in  it.  Daily, 
some  of  its  members  die  while  new  ones  are  born ;  some  move 
in  and  others  move  away.  When  the  number  added  is  greater 
than  the  number  lost,  the  community  grows  in  size.  Do  you 
know  that  this  is  true  also  of  the  communities  or  colonies  of  cells 
that  compose  the  living  body  ?  Many  millions  of  the  cells  die 
in  the  course  of  a  single  day.  Seven  million  blood  cells  die 
every  second  of  our  lives.  If  no  new  ones  were  supplied  to  take 
their  places,  what  would  happen  to  the  body?  Besides  the 
cells  needed  to  take  the  place  of  those  that  have  died,  the  child 
or  the  young  animal  needs  an  increase  of  cells  to  provide  for 
its  growth.  Why? 

All  living  things  grow.     This  is  one  of  the  chief  differences 
between  organic  and  inorganic  objects.     A  lifeless  object,  such 
as  a  rock  or  mountain,  does  not  grow,  although  it  How  we 
may  increase  in  size  by  the  simple  addition  of  material.  Srow 
Living  things,  plants  and  animals,  grow  by  taking  material  into 
themselves   and   changing  it  into   their  own   substance.     The 
growth  of  a  human  being,  from  the  very  beginning  until  he  reaches 
full  stature,  can  take  place  only  through  the  making  of  tissues 
from  the  food  he  eats. 

All  the  cells  of  the  body  that  are  living  and  active,  need 
food  to  maintain  their  life  and  to  supply  them  with  energy  for 


12  KEEPING  THE  BODY  IN  HEALTH 

their  work,  and  to  furnish  fuel  to  keep  them  warm.     Hunger  is 
the  appeal  of  the  body  for  more  fuel  and  building  material. 

The  living  body  is  like  both  a  house  and  a  machine.  A 
machine  wears  out  much  more  quickly  than  a  building,  for  the 
reason  that  it  works.  The  work  performed  in  and  by  the  body 
wears  it  out,  so  that  it  is  in  constant  need  of  repairs.  The  wear- 
ing out  process  is  so  great  that  the  entire  body  is  rebuilt  many 
times  during  a  long  life.  How  is  the  material  for  the  necessary 
repairs  supplied  ? 

The  living  human  body  is  always  warm.  In  summer  or 
winter,  no  matter  what  the  temperature  of  the  surrounding  air 
may  be,  the  body  temperature  is  always  maintained  at  nearly 
100  degrees.  In  Building  Health  Habits  you  have  learned 
about  the  combustion,  or  slow  burning,  by  which  the  body  heat 
is  kept  up.  To  produce  heat  something  must  be  consumed. 
The  life  fire  that  warms  the  body  consumes  its  cells  just  as 
burning  consumes  a  candle  or  as  fuel  is  consumed  in  a  stove. 
Of  course,  a  constant  supply  of  fuel  is  needed  to  keep  this  life 
fire  steadily  burning. 

What  is  ordinarily  spoken  of  as  fire  is  an  active  burning,  ac- 
companied by  a  flame.  When  combustion  is  less  active  the 
heat  is  less  intense,  and  there  may  be  no  visible  flame.  It  is  by 
this  latter  kind  of  combustion  that  a  dead  tree,  lying  upon  the 
ground  in  the  woods,  is  gradually  consumed.  In  time  it  will 
disappear  as  completely  as  if  it  had  been  burned  up  in  a  stove. 
The  amount  of  heat  produced  by  the  burning  of  a  tree  is  just 
the  same,  whether  it  rots  in  the  forest  or  is  burned  in  a  furnace ; 
but  in  the  furnace  the  heat  is  given  off  in  a  much  shorter 
time. 

Another  important  source  of  bodily  waste  is  work.  The  loco- 
motive cannot  pull  its  train  of  cars  without  using  coal.  The 
amount  of  fuel  consumed  by  a  locomotive  is  in  proportion  to 


THE   MAINTENANCE  OF  THE   BODY  13 

the  amount  of  work  it  does.     So  the  locomotive  which  pulls 
the  largest  train  consumes  the  most  coal.     Just  as  the  loco- 
motive gets  its  power  to  work  from  the  fuel  that  is  How  the 
burned  under  its  boiler,  so  the  body  gets  its  power  to  cells  get 
work  from  the  food  that  is  eaten.    All  the  work  done  in  their 
and  by  the  body  consumes  materials  that  must  be  re-  energy 
plenished  by  the  food  supply.     The  body,  therefore,  has  as  its 
source  of  energy,  — food.     The  greater  the  amount  of  work  done, 
the  greater  the  amount  of  food  needed.     Think  for  a  moment  of 
the  tremendous  amount  of  work  performed  daily  by  the  cells  of 
the  body.     It  has  been  carefully  estimated  that  the  work  which 
the  body  is  capable  of  doing  daily  is  equal  to  the  lifting  of  900 
tons  to  a  height  of  one  foot.     More  than  one  tenth  of  this  work 
is  done  by  the  heart,  which  is  constantly  at  work,  apparently 
without  rest  day  or  night,  pumping  the  blood  to  every  part 
of  the  body.     The  work  of  the  lungs,  and  of  the  muscles  that 
move    the   breathing   apparatus,  also  goes  on   every  moment 
during  life.      The  balance   of    the  work    is   done  by   the   di- 
gestive   organs,    the   glands,    the   brain,    the   nerves,  and   the 
muscles. 

We  see  then  that  there  are  two  things  that  the  food  supplies 
to  the  bo.dy :  material  for  the  building  of  body  tissue,  —  bone, 
muscle,  blood,  brain,  and  all  the  organs  of  the  body ;  and  energy, 
which  is  used  in  the  body  in  many  different  ways,  —  producing 
heat,  doing  muscular  and  mental  work,  keeping  the  heart  beat- 
ing, and  enabling  all  the  different  organs  and  glands  of  the  body 
to  perform  their  work. 

By  chemical  examination,  the  body  has  been  found  to  be 
made  up  of  many  different  substances,  chief  of  which  are  oxygen, 
hydrogen,  carbon,  nitrogen,  and  lime.  As  you  look  carefully 
over  the  following  table,  note  the  amount  of  each  one  of  the 
different  substances  named  contained  in  the  body  of  a  person 


14  KEEPING  THE  BODY  IN  HEALTH 

weighing  150  pounds,  and  remember  that  each  one  is  absolutely 
essential,  although  the  amount  needed  may  be  very  small. 

Oxygen 97-5  Pounds 

Carbon 27.0  Pounds 

Hydrogen 15.0  Pounds 

Nitrogen 4-5  Pounds 

Calcium 3.0  Pounds 

Phosphorus 1.5  Pounds 

Potassium 5  Pound 

Sulphur 4  Pound 

Chlorine 2  Pound 

Sodium 2  Pound 

Magnesium 1.2  Ounces 

Iron  .     .     .    ' i  Ounce 

Fluorine Traces 

Silicon Traces 

Let  us  now  see  where  we  get  the  material  that  forms  our 
bodies.  Every  particle  of  it  comes  from  the  earth,  the  air,  and 
Thesources  *ne  water-  The  human  body,  however,  does  not  have 
of  the  ma-  the  power  to  make  living  cells  out  of  earth  and  air. 
terial  in  Here,  for  instance,  are  a  piece  of  bread  and  a  piece  of 
coal.  Both  contain  material  and  energy,  and  some  of 
the  same  elements.  Yet  one  is  a  food,  and  the  other,  is  not  a 
food.  The  coal  may  be  burned  in  a  locomotive  to  furnish  both 
heat  and  energy,  but  cannot  be  used  in  the  human  body. 

The  plant  is  the  workshop  or  factory  where  the  food  for 
animals  is  produced.  The  material  coming  from  the  earth,  the 
air,  and  the  water  must  first  become  a  part  of  the  plant  before 
it  can  be  used  by  animals  as  food.  A  plant,  for  example,  takes 
carbonic  acid  gas  from  the  air.  This  is  not  a  food.  From  the 
soil  the  plant  takes  up  water,  combines  it  with  the  carbonic  acid 
gas,  and  makes  starch,  which  is  a  food. 

The  plant  makes  food  in  its  leaves,  which  serve  as  its  stomach 


THE  MAINTENANCE  OF  THE  BODY  15 

and  lungs.  The  green  color  of  leaves  is  due  to  the  presence 
of  little  grains  of  chlorophyll  (klo'ro-fil).  Each  of  these  little 
grains  is  a  wonderful  laboratory  where  food  for  the  plant  is 
made  out  of  carbonic  acid  gas  and  water.  The  carbonic  acid 
gas  is  taken  from  the  air,  while  the  water  comes  to  the  leaves 
through  the  roots. 

Sunlight,  the  great  source  of  energy,  cannot  be  absorbed 
directly  by  the  body.  The  chlorophyll  grains  capture  the  sun- 
light and  store  the  energy  which  it  brings.  Every  vegetable 
product,  as  wheat,  corn,  and  potato,  is  such  a  storehouse. 
Every  fruit,  every  seed,  every  nut,  is  a  little  bundle  of  concen- 
trated light,  stored  until  it  is  needed  for  the  growth  and  devel- 
opment of  a  new  plant  or  to  furnish  heat  and  energy  to  some 
member  of  the  animal  kingdom. 

This  calls  our  attention  to  an  important  difference  between 
plants  and  animals.     A  plant  is  a  food  producer,  a  storehouse  of 
energy.     An  animal  is  a  food  consumer,  an  expender  of  pjants  the 
energy.     Animals,  although  they  are  sometimes  used  only  food 
for  food,  do  not  make  foods.     A  plant  is  the  only  real  Pr<>ducers 
food  factory.     A  lion,  in  dining  upon  an  antelope,  is  only  eating 
at  secondhand   the  grass   and  herbs  which   the   antelope  has 
eaten.     A  man,  in  eating  roast  beef,  is  taking  at  secondhand  the 
corn  upon  which  the  ox  was  fed. 

We  must  now  study  the  substances  that  are  adapted  to  serve 
as   food    for   man.     A  substance  which  can  be  used  by  the  body 
to  furnish  it  with  material  for  building  or  repairs  or  composi- 
with  energy  for  heat    and  work  is  called  a  nutrient,  tion  of 
We  have  seen  that  one  purpose  of  food  is  to  supply  foods 
the  body  with  warmth  and  with  power  to  work.     These  special 
needs  are  met  by  two  classes  of  nutrients,  carbohydrates  (starch, 
dextrin,  and  sugar)  and  fats.    The  building  material  for  the  body 
is  furnished  by  a  third  class  of  nutrients  called  proteins.    These 


1 6  KEEPING  THE  BODY  IN  HEALTH 

-  carbohydrates,  fats,  and  proteins  —  are  the  three  great 
classes  of  nutrients. 

In  addition  there  are  — 

Salts,  which  are  essential  not  only  for  the  bones,  but  for  all 
living  tissues  of  the  body.  (By  salts  we  do  not  mean  "  table 
salt,"  but  organic  combinations  of  lime,  magnesia,  phosphorus, 
potash,  iron,  and  other  elements.) 

Flavoring  Substances,  which  render  the  food  agreeable  to  the 
taste. 

Cellulose,  an  indigestible  substance  found  in  all  vegetable 
foods,  which  is  highly  essential  to  give  bulk  to  the  food  mass, 
to  stimulate  the  activity  of  the  stomach  and  intestines,  and 
to  enable  the  colon  to  dispose  of  body  refuse. 

Vitamines,  subtle  substances  which  are  found  in  fresh,  un- 
cooked foods,  and  which  are  absolutely  necessary  for  the  com- 
plete nourishment  of  the  body.  These  substances  are  so  re- 
fined and  so  active  that  little  is  known  about  them  except 
the  fact  that  they  exist  and  that  some  of  them  are  likely  to  be 
destroyed  by  cooking.  Sailors  get  scurvy  by  the  exclusive  use 
of  cooked  food. 

Starch  is  the  most  abundant  of  the  food  elements.  It  is  found 
in  all  grains  and  vegetables,  and  in  green  fruits,  though  not 
in  ripe  fruits.  Starch  consists  of  little  granules,  each  one  of 
which  is  inclosed  in  an  envelope  of  cellulose,  which  is  the  sub- 
stance from  which  paper  is  made.  The  process  of  cooking 
breaks  open  the  envelope  and  releases  the  starch,  which  can 
then  be  reached  and  acted  upon  by  the  digestive  fluids  in  the 
body.  The  accompanying  picture  shows  different  kinds  of 
starch  granules.  The  starch  particles  of  the  potato  are  much 
larger  than  those  of  grains  and  are  much  more  easily  digested. 
The  picture  shows  the  change  that  occurs  in  starch  granules  as 
a  result  of  cooking. 


THE   MAINTENANCE   OF  THE   BODY  17 

Sugar,  although  very  unlike  starch  in  appearance  and  taste, 
is  almost  like  it  in  composition.  When  starch  is  digested  it 
is  made  into  sugar.  Sugar  is  found  in  all  fruits  and  in  some 
vegetables,  such  as  corn,  beets,  and  sweet  potatoes.  There  are 
different  kinds  of  sugars.  The  sugar  of  fruits  is  called  fruit 
sugar.  A  sweet  substance  found  in  milk  is  known  as  milk  sugar. 


A  3  0 

THIS  PICTURE  SHOWS  THE  CHANGE  THAT  IS  MADE  IN  STARCH  CELLS  OF  POTATOES  BY  COOKING. 

A,  cells  of  raw  potato;   B,  cells  of  partially  cooked  potato;  C,  cells  of  boiled  potato 

A  peculiar  sugar  produced  in  the  sprouting  or  malting  of  grain 
is  called  malt  sugar  or  maltose.  Sugar  furnished  by  the  sugar 
cane,  the  beet  root,  or  the  sap  of  the  maple  tree  is  known  as  cane 
sugar. 

Fats  are  found  in  both  animal  and  vegetable  foods.  Butter, 
lard,  and  suet  are  the  principal  forms  of  animal  fats  used  as 
foods.  Vegetable  oils  come  chiefly  from  nuts,  from  various 
seeds  such  as  the  cotton  seed,  from  the  soy  bean,  and  from  oily 
fruits  such  as  the  olive. 

Proteins  contain  the  carbon,  hydrogen,  and  oxygen  found  in 
fats,  starch,  and  sugar.  In  addition  to  these  they  also  contain 
nitrogen,  and  because  of  this  they  are  sometimes  called  nitroge- 
nous foods.  Proteins  are  abundant  in  animal  foods,  —  lean 
meat,  milk,  cheese,  and  eggs.  Of  the  foods  obtained  from  plants, 
proteins  are  found  chiefly  in  nuts,  peas,  beans,  and  lentils, 


i8 


KEEPING  THE  BODY  IN  HEALTH 


though  they  are  contained  also  in  all  grains  and  in  very  small 
quantities  in  most  vegetables.  Phosphorus  and  sulphur  are  also 
found  in  proteins.  The  iron,  lime,  and  salts  of  food  are  mostly 
found  with  the  proteins. 

LIST  OF  COMMON  FOODS  RICH  IN  PROTEINS,  FATS,  AND  CARBOHYDRATES 


PROTEINS 


FATS 


CARBOHYDRATES 


(Animal) 


Milk 
Cheese 

Eggs 
Meat 


(Vegetable) 

Legumes  (dried  peas, 
beans,  especially 
the  soy  bean,  len- 
tils) 

Nuts 

Oatmeal 

Wheat 


(Animal) 

Milk 
Cream 
Cheese 
Butter 
Egg  yolk 
Suet 
Lard 
Fat  meat 

(Vegetable) 

Nuts 

Coconut  oil 

Olive  oil 

Other  vegetable  oils 

Oleomargarine 


(Animal) 

Milk  sugar  in  milk 
Honey 


(Vegetable) 

All  cereals;  all  foods  made 
from  cereals ;  starchy  vege- 
tables, particularly  the  Irish 
potato,  the  sweet  potato, 
green  corn,  green  peas; 
legumes ;  sweet  fruits,  fig, 
banana,  apple,  prune,  pear, 
raisin,  date ;  sugars ;  chest- 
nuts, and  some  other  nuts 


The  carbohydrates  and  fats,  which  are  composed  of  the  same 
elements  (carbon,  hydrogen,  oxygen),  serve  the  same  purpose 
Uses  of  the  in  the  body.  They  are  the  fuel  or  energy-giving 
different  foods,  which  are  burned  up  in  the  body  to  furnish  it 
with  warmth  and  with  power  to  work.  When  not 
needed  for  immediate  use,  they  may  be  stored  up  in  the  tissues 


THE  MAINTENANCE  OF  THE  BODY  19 

of  the  body,  just  as  coal  is  stored  up  in  the  tender  of  a  loco- 
motive to  be  used  as  needed. 

The  proteins  are  a  most  important  class  of  nutrients  because 
they  furnish  the  building  material  for  the  body.  Just  as  the 
carbohydrates  and  fats  correspond  to  the  coal  burned  in  the 
locomotive,  the  proteins  correspond  to  the  iron,  brass,  and  other 
materials  out  of  which  the  locomotive  is  made.  Nitrogen, 
which  is  contained  only  in  proteins,  is  an  element  needed  for  cell 
building,  and  it  is  this  that  gives  the  protein  foods  their  great 
importance.  A  growing  child,  whose  body  is  in  process  of 
building,  needs  these  nitrogenous  foods  in  larger  quantities  than 
a  person  who  is  full-grown  and  needs  only  the  material  necessary 
for  repairs.  The  foods  which  nature  has  provided  for  the  use 
of  young  animals  are  rich  in  proteins.  The  white  or  albumen 
of  the  egg,  out  of  which  the  young  chick  is  to  be  formed,  is 
composed  wholly  of  this  element.  Milk,  which  is  the  natural 
food  for  young  animals,  also  contains  an  abundance  of  protein. 

Proteins  may  be  burned  in  the  body  to  furnish  energy,  but 
their  chief  use  is  for  building.  There  is  no  provision  in  the  body 
for  the  storing  up  of  the  proteins,  or  building  foods,  as  there  is 
for  the  storage  of  the  fuel  foods,  hence  it  is  important  to  take 
just  the  proper  amount  each  day,  avoiding  excess. 

Certain  minerals  are  needed  in  small -amounts.  Of  these  com- 
mon salt  is  the  one  most  familiar  to  us.  This  is  found  in  suffi- 
cient quantities  in  most  of  our  foods,  but  we  often  add  more  in 
cooking  and  eating,  —  sometimes  too  much.  Lime,  which  is  espe- 
cially needed  by  a  growing  child  for  the  building  up  of  his  bones, 
is  found  chiefly  in  milk,  grains,  and  eggs.  A  small  but  very 
necessary  amount  of  iron  is  needed  for  the  formation  of  the 
red  blood  cells.  This  is  found  especially  in  the  yolk  of  egg  and 
in  the  green  parts  of  vegetables. 

Another  substance  very  necessary  to  the  body  is  water,  which 


20 


KEEPING  THE  BODY  IN  HEALTH 


as  you  know  comprises  a  large  part  of  the  body.  Water  is 
lost  from  the  body  chiefly  in  the  removal  of  wastes.  It  is 
also  constantly  passing  off  through  the  lungs  and  skin  in  the 
form  of  an  invisible  vapor.  The  moisture  of  the  breath  can  be 

seen  when  one  is  in  the  open 
air  on  a  frosty  morning. 
When  one  exercises  vio- 
lently, or  is  exposed  to  great 
heat,  the  water  thrown  off 
by  the  skin  becomes  visible 
in  the  form  of  perspiration. 
The  amount  lost  daily  is 
three  or  four  pints,  and  this 
loss  must  be  made  good  by 
drinking  water  or  getting 
it  in  food.  We  get  a  con- 
siderable amount  in  our 
foods.  Even  what  are  called 
dry  foods,  such  as  rice  and 
beans,  contain  some  water, 
and  other  foods  are  largely 
composed  of  it.  Potatoes, 
for  instance,  are  more  than 

per    CCnt    Water. 
Another      SUbstaUCC      that 

tO 
Qf       ^ 


YOU  CAN  SEE  FROM  THESE  PICTURES  WHAT  HARM 
ALCOHOL  DOES  TO  SUCH  DELICATE  ORGANS  AS 
THE  STOMACH.  THE  UPPER  PICTURE  SHOWS  A  .  11 

HEALTHY    STOMACH    AND    THE    LOWER    ONE    THE     IS      absolutely 
INFLAMED    STOMACH  OF  A  DRUNKARD. 


cells  is  oxygen,  which  we  get  from  the  air.     If  the  supply  of 
oxygen  is  cut  off  from  the  body  for  only  a  few  moments,  the  life 
fire  dies  out.     How  the  necessary  oxygen  is  supplied  to  the  cells 
and  what  use  is  made  of  it  will  be  told  in  another  chapter. 
A  poison  is  just  the  opposite  of  a  food.     Instead  of  furnishing 


THE  MAINTENANCE  OF  THE  BODY  21 

the  body  with  nourishment,  it  interferes  with  the  life  and  work 
of  the  cells,  disturbing  them  in  such  a  way  as  to  cause  Poisons 
sickness  and  death.     A  true  food  must  not  contain  the  op- 
any  substance  that  is  in  any  way  harmful  to  the  positeof 
body. 

In  recent  years  there  has  been  much  discussion  as  to  whether 
or  not  alcohol  is  a  food.  Alcohol,  as  we  have  already  learned, 
paralyzes  'the  cells  that  make  bone  and  flesh.  All  the  delicate 
organs  by  which  the  life  work  of  the  body  is  carried  on  are  in- 
jured by  it  and  hindered  in  their  work.  Not  only  are  the  organs 
injured  and  weakened  by  it,  but  the  task  of  removing  this  in- 
jurious substance  from  the  body  adds  greatly  to  their  work. 

No  food  prepared  for  us  by  Nature  is  composed  solely  of  one 
of  the  nutrients  that  we  have  been  studying.  They  are  com- 
bined in  the  foods  in  the  way  in  which  they  will  best  meet  the 
needs  of  the  body.  We  might  dine  with  a  king  and  have  a  very 
elaborate  menu  with  the  food  prepared  in  many  different  ways, 
but  the  food  cannot  have  in  it  more  than  these  few  simple  nu- 
trients that  we  have  studied. 

HEALTH  PROBLEMS 

1.  Have  you  noticed  how  very  hungry  growing  puppies  and  kittens 
are  all  the  time ?     Explain.     Is  this  true  of  all  growing  animals?     Why? 

2.  Suppose  one  could  not  eat  any  food,  what  would  happen  to  him? 
Why  ?     Would  it  happen  more  quickly  if  he  had  to  work  hard  than  if  he 
were  idle  ?     Why  ? 

3.  Have  you  ever  had  a  physician  "  take  your  temperature"?     If  so, 
why  did  he  do  it  ? 

4.  When  one  goes  out  into  zero  weather,  how  is  the  warmth  of  the 
body  kept  up  to  about   99  degrees?    What  would  happen  if  the  bodily 
temperature  should  drop  a  few  degrees? 

5.  Think  of  some  way  to  prove  that  the  cells  feed  on  the  food  taken 
into  the  body. 

6.  Are  you  more  hungry  when  you  work  or  play  hard,  or  are  out  in 


22  KEEPING  THE  BODY  IN  HEALTH 

the  cold  much,  than  when  you  stay  in  a  warm  house  and  do  no  work? 
Explain. 

7.  Can  you  tell  starchy  foods,  fats,  foods  rich  in  sugar,  and  those  rich 
in  protein  by  the  sense  of  taste  alone  ?    Explain. 

8.  Should  a  growing  boy  eat  more  eggs,  peas,  beans,  cheese,  and  such 
foods  than  a  full-grown  man  who  is  doing  very  little  muscular  work  ?     Why  ? 

9.  Show  by  an  experiment  that  a  potato,  or  an  apple,  or  a  cucumber 
is  largely  water. 

REVIEW  QUESTIONS 

1.  What  is  necessary  that  a  living  thing,  whether  plant  or  animal,  may 
grow? 

2.  What  do  living  cells  need  in  order  to  maintain  their  life? 

3.  Why  is  the  living  body  like  both  a  house  and  a  machine? 

4.  What  is  the  normal  temperature  of  the  body? 

5.  How  is  heat  produced  in  the  body? 

6.  What  is  the  difference  between  the  burning  of  fuel  in  the  human 
body  and  the  burning  of  fuel  in  a  stove  ? 

7.  How  do  the  cells  get  the  energy  for  their  work? 

8.  What  happens  in  the  body  when  work  is  done?     Show  that  the 
body  at  work  is  something  like  a  locomotive  pulling  cars. 

9.  What  organs  of  the  body  are  constantly  at  work  ? 

10.  What  two  things  does  food  supply  to  the  body? 

11.  What  must  happen  to  the  material  coming  from  the  earth,  the  air, 
and  the  water  before  it  can  be  used  by  animals  as  food  ? 

12.  How  does  a  plant  make  starch  for  our  use? 

13.  Which  nutrient  supplies  the  building  material  for  the  body  ?    Which 
supplies  the  warmth  and  power?    Which  the  material  for  making  bones 
and  teeth? 

14.  Where  is  starch  found  abundantly?    Discuss  starch  as  a  food. 

15.  In  what  fruits  and  vegetables  is  sugar  found  ?    Name  the  kinds. 

16.  In  what  foods  are  the  fats  found ?    The  proteins? 

17.  Which  of  the  classes  of  nutrients  does  the  growing  animal  need 
especially  ? 

18.  Mention  the  minerals  which  are  needed  in  the  body.     In  what  foods 
are  they  found? 

19.  How  does  a  poison  affect  the  body  ?    Is  alcohol  a  food  or  is  it  a  poison  ? 


CHAPTER  III 

How  FOOD  BECOMES  LIVING  TISSUE 

THE  food  substances  or  nutrients  about  which  you  have  been 
learning  cannot  be  taken  up  just  as  they  are  and  used  by  the 
cells  as  food.  A  great  deal  of  preparatory  work  is  necessary. 
This  work  of  preparation  is  called  digestion.  We  have  already 
seen  how  the  work  of  the  body  is  divided  among  the  different 
groups  of  cells  that  form  the  organs  of  the  body.  The  groups 
whose  work  it  is  to  prepare  the  food  are  called  the  digestive 
organs. 

If  you  have  visited  a  large  bakery  establishment,  you  have 
seen  how  the  work  is  divided  among  the  different  workers. 
One  worker  attends  solely  to  the  mixing  and  kneading  of  the 
dough,  which  is  then  passed  to  another  who  spends  his  time 
in  rolling  it  out  to  the  required  thickness.  Another  worker 
then  takes  it  and  cuts  it  into  pieces  of  the  right  size  and  shape 
and  passes  it  to  yet  another  who  superintends  the  baking.  In 
like  manner  the  food  you  eat  is  passed  from  one  to  another  of  the 
cell  groups,  called  the  digestive  organs ,  and  each  group  has  some 
special  part  of  the  work  of  preparation,  or  digestion,  to  perform. 

The  long,  narrow  tube  in  which  the  work  of  digestion  takes 
place  is  called  the  alimentary  canal  or   food    tube.      Aliment 
means  food,  and  the  alimentary  canal  is  simply  the  The  food 
food  channel  of  the  body.     It  is  from  twenty-five  canal 
to  thirty  feet  long  and  is  lined  throughout  with  a  fine  pink  lining 
called  mucous  membrane,  which  you  can  see  in  the  mouth.     This 

23 


KEEPING  THE  BODY  IN  HEALTH 


Uver 


Co/on 


is  always  kept  moist, 
so  that  the  food  may 
easily  be  moved  along 
the  tube. 

The  cell  groups 
•whose  work  it  is  to 
prepare  the  food  are 
stationed  at  various 
places  along  the  route 

•Stomach    that     the     f°°d     must 

travel,  just  where  their 
services  are  needed. 
Each  group  prepares 
Pancreas  a  special  kind  of  fluid 
or  juice  which  it  pours 

intestine      OUt     Upon     the     food. 

These  fluids  are  called 
the  digestive  juices. 
There  are  five  diges- 
tive organs,  and  so 
there  are  five  differ- 
ent digestive  juices. 

All  the  food  must 
be  soaked  up  or  ab- 
sorbed by  the  walls  of 
the  canal  in  order  to 
pass  through  it  into 
the  body  for  the  use 
of  the  cells,  which  can 

take  their  food  only  in  a  liquid  form.  Most  of  our  foods 
consist  of  solid  particles  which  do  not  dissolve  in  water.  Put 
some  sugar  in  a  glass  of  water,  and  you  will  find  that  after 


HOW  FOOD  BECOMES  LIVING  TISSUE  2$ 

a  few  minutes  the  sugar  seemingly  completely  disappears. 
It  is  dissolved  in  the  water,  and  you  can  detect  its  presence 
only  by  the  taste.  If  you  treat  a  piece  of  bread  Digestive 
in  the  same  way,  you  will  see  that  it  does  not  dis-  3uices 
solve  in  the  water  but  only  mixes  with  it.  If  you  strain 
through  a  fine  sieve  or  cloth  the  water  containing  the  sugar, 
both  sugar  and  water  will  pass  through  together  and  there 
will  be  nothing  left  on  the  cloth.  But  if  you  strain  in  the 
same  way  the  water  with  which  the  bread  has  been  mixed, 
the  water  will  pass  through  the  cloth  and  most  of  the  bread  will 
remain  behind. 

The  work  of  digestion  is  simply  the  work  of  changing  the  in- 
soluble (look  up  the  meaning  of  insoluble)  food  substances  into 
substances  that  will  readily  dissolve  and  so  pass  easily  through 
the  walls  of  the  food  tube  into  the  blood. 

At  the  very  entrance  of  the  food  canal  is  a  station  where  the 
food  must  tarry  for  a  while  and  be  worked  over  before  it  starts 
on  its  journey  through  the  body.     This  station  is  The  first 
the  mouth,  the  first  of  the  digestive  organs.     The  step  in 
work  done  in  the  mouth,  as  we  learned  in  Building  dlgestion 
Health  Habits,  is  of  the  utmost  importance,  because  all  the  rest 
of  the  work  of  digestion  depends  upon  thorough  preparation 
of  the  food  in  the  mouth. 

An  important  part  of  this  work  is  the  chewing  or  mastication 
of  the  food,  which  is  done  by  the  teeth.  An  infant  is  born  with- 
out teeth.  Between  the  ages  of  seven  months  and  two  years 
the  temporary  or  milk  teeth,  twenty  in  number,  make  their 
appearance.  By  the  twelfth  year  these  temporary  teeth  have 
given  place  to  the  permanent  set.  A  complete  set  of  permanent 
teeth  in  an  adult  consists  of  thirty- two  teeth.  Each  jaw  con- 
tains four  front  teeth,  called  incisors  or  cutting  teeth ;  two  cus- 
pids, one  on  each  side  of  the  incisors;  four  bicuspids,  two  on 


26 


KEEPING  THE  BODY  IN  HEALTH 


Jfoof 


each  side;   and  six  double  teeth,  three  on  each  side,  called  the 

molars  or  grinding  teeth. 

The  teeth  are  helped  in  the  work  of  mastication  by  the  tongue, 

which  moves  the  food  about,  passing  it  from  side  to  side  of  the 

mouth  until  it  is  all  thoroughly 
chewed.  In  the  tongue  also  are 
taste  buds  by  which  the  different 
flavors  in  foods  are  detected. 

The  work  of  mastication  is  also 
assisted  by  the  saliva,  the  first  of 
the   digestive  juices   to  j^e  work 
be  poured  out  upon  the  of  the 
food.  This  moistens  and  saliva 
softens  the  food,  so  that  it  is  more 

A  SECTION  OF  A  TOOTH.      WHAT    IS    THE  .,  ,       .      A 

USE  OF  THE  ENAMEL?   OF  THE  DEN-  easily  made  into  a  creamy  pulp. 

TINE?    WHAT  is  THE  TROUBLE  WHEN         The   saliva,   does   much    morp    to 

A  TOOTH  ACHES? 

the  food  than  merely  to  moisten 

it.  If  you  chew  a  hard  crust  of  bread  thoroughly,  you  will  notice 
that  after  a  while  it  becomes  quite  sweet  to  the  taste.  This  is 
because  some  of  the  starch  in  it  has  actually  been  changed  by 
the  saliva  into  the  kind  of  sugar  called  maltose. 

The  groups  of  cells  which  prepare  the  saliva  and  pour  it  on 
the  food  are  called  salivary  glands.  When  we  are  eating  we 
should  be  careful  not  to  discourage  these  glands  from  working 
by  drinking  large  quantities  of  liquid.  Dry  food  does  not  need 
to  be  "washed  down,"  though  many  people  seem  to  think  so. 
Saliva  is  formed  and  poured  out  each  moment  in  quantities 
exactly  suited  to  the  nature  and  quality  of  the  food  that  is  being 
chewed.  If  the  food  is  already  moist,  the  quantity  of  saliva 
produced  will  be  very  small.  Why?  When  liquid  foods  like 
milk  are  taken,  little  or  no  saliva  will  be  produced.  Dry  and 
highly  flavored  foods  cause  the  salivary  glands  to  pour  out  an 


HOW  FOOD  BECOMES  LIVING  TISSUE  27 

abundance  of  saliva.  Why?  Food  containing  starch,  which 
needs  an  abundant  outflow  of  saliva,  should  of  course  be  eaten 
dry  and  should  be  thoroughly  chewed.  It  is  very  necessary  that 
the  food  should  remain  in  the  mouth  long  enough  for  a  sufficient 
amount  of  saliva  to  be  poured  out 
upon  it,  and  that  it  should  be  so 
thoroughly  chewed  that  the  saliva 
will  become  mingled  with  every 
part  of  it. 

The  process  of  starch  digestion 
is  not  confined  to  animals  alone. 
Most  plants  are  capable  of  trans- 
forming starch  into  sugar.  This 
change  always  takes  place  in  the 
ripening  of  fruits.  The  starch  of 
the  green  apple,  for  example,  is 
changed  into  the  sweet,  wholesome 
sugar  that  flavors  the  ripe  fruit. 
By  a  similar  process,  the  starch  Tms  PICTURE  OF  THE  UPPER  SURFACE 
stored  up  in  the  fall  by  the  roots  of  OF  THE  TONGUE  SHOWS  THE  TASTE 

BUDS  ESPECIALLY.      CAN  YOU  TASTE 

the  maple  -tree  IS  in  the  spring  Con-         ANYTHING  WITH  THE  VERY  TIP  OF 

verted  into  sugar  and  carried  up  in      raE  TONGUE? 
the  sap.     It  is  in  this  way  also  that  the  honey  of  plants  is  formed 
and  deposited  in  the  flower  cups  from  which  it  is  collected  by 
the  bee. 

When  the  food  has  been  sufficiently  acted  upon  in  the  mouth, 
it  passes  on  its  way  through  the  alimentary  canal.  The  muscles 
at  the  back  of  the  mouth  seize  the  food  and  carry  it  into  the 
gullet  or  esophagus,  —  the  name  given  to  that  part  of  the  food 
canal  that  connects  the  mouth  with  the  stomach. 

The  muscles  at  the  back  of  the  mouth  seem  to  act  as  gate- 
keepers to  guard  the  entrance  to  the  esophagus.  At  frequent 


28  KEEPING  THE  BODY  IN  HEALTH 

intervals  during  mastication  they  move  the  food  forward  in  the 
mouth,  keeping  it  there  until  it  has  been  thoroughly  chewed, 
The  path  after  which  they  are  ready  to  let  it  pass  on.  The 
to  the  food  then  seems  to  "  swallow  itself,"  without  any  effort 

stomach  on  our  part.  People  very  often  force  the  food  from 
the  mouth  back  into  the  esophagus  before  it  has  had  the 
proper  mouth  treatment.  If  the  act  of  swallowing  requires  a 
conscious  effort,  we  may  be  sure  that  the  food  has  not  been  in 
the  mouth  long  enough. 

The  esophagus  is  not  a  tube  through  which  the  food  is  simply 
dropped  into  the  stomach.  The  walls  of  the  entire  alimentary 
canal  are  composed,  in  part,  of  muscles,  arranged  in  such  a  way 
as  will  best  assist  the  work  of  the  different  digestive  organs. 
By  means  of  the  muscles  in  the  esophagus,  the  food  is  moved 
along  until  it  reaches  the  second  food  station,  —  the  stomach. 

To  form  the  stomach,  the  food  tube  is  widened  into  a  broad 
pouch,  as  shown  in  the  picture  on  page  24.  At  each  end  of  the 
pouch  is  a  strong  circular  muscle  which  guards  the  entrance 
and  the  exit.  The  entrance  is  called  the  cardiac  opening,  and 
the  exit  is  called  the  pylorus,  meaning  the  " gatekeeper."  The 
large  end  of  the  stomach  near  the  cardiac  opening,  where  diges- 
tion chiefly  takes  place,  is  called  the  cardiac  end;  the  lower 
and  narrower  end,  which  is  chiefly  composed  of  very  strong 
muscles,  is  the  pyloric  end. 

Even  before  the  food  reaches  the  stomach,  a  very  important 
work  of  preparation  has  been  going  on  there.  Nature  has  in- 
Stomach  stalled  in  the  body,  to  help  on  the  work  of  digestion, 
digestion  a  kind  of  signaling  system  by  means  of  which  the 
digestive  organs  are  given  notice  when  food  is  to  be  expected.  The 
cell  workers  then  at  once  begin  active  preparations  for  their  work. 

You  have  noticed  how,  at  the  mere  sight  or  odor  of  appetizing 
food  —  when  you  smell  a  good  dinner  cooking,  for  example  — 


HOW  FOOD  BECOMES  LIVING  TISSUE  29 

the  mouth  begins  to  " water."  This  is  because  a  sort  of  tele- 
graphic message  has  been  sent  from  the  brain  to  the  salivary 
glands,  and  they  have  immediately  begun  to  pour  out  a  quantity 
of  saliva  in  readiness  for  the  food  that  is  expected.  Something 
of  the  same  kind  takes  place  also  in  the  stomach.  A  Russian 
scientist,  Professor  Pavlov,  made  many  experiments  upon  dogs 
and  men  by  means  of  which  he  discovered  some  very  interesting 
facts  about  the  work  of  digestion,  especially  that  part  of  the  work 
that  is  done  in  the  stomach.  He  made  a  device  by  which  he 
could  actually  see  into  the  stomach  of  a  dog  and  find  out  exactly 
what  took  place  there.  When  the  dog  was  hungry,  the  mere 
sight  or  smell  of  food  caused  the  stomach,  as  well  as  the  mouth, 
to  secrete  its  digestive  juice,  and  it  continued  to  do  this  all  the 
time  the  food  was  being  chewed.  By  the  time  the  food  actually 
reached  the  stomach,  there  was  a  quantity  of  digestive  juice 
ready  for  it. 

The  digestive  fluid  that  is  poured  upon  the  food  while  it  is  in 
the  stomach  is  called  gastric  juice.  It  makes  its  first  appearance 
upon  the  walls  of  the  stomach  in  little  drops,  like  tiny  beads  of 
sweat  upon  the  skin.  As  the  quantity  increases,  the  drops  run 
together  and  trickle  down  the  sides  of  the  stomach  in  little 
streams.  The  membrane  lining  the  stomach,  when  seen  under  a 
microscope,  is  found  to  have  many  minute  openings.  Each  of 
these  openings  is  connected  with  a  narrow  tube  which  extends 
into  the  walls  of  the  stomach,  making  a  kind  of  pocket.  This 
little  pocket  is  lined  with  living  cells,  which  during  the  process  of 
digestion  are  actively  at  work  making  the  gastric  juice. 

The  gastric  juice  has  no  action  upon  starch,  sugar,  or  fats, 
and  only  digests  some  of  the  protein  of  the  food.     There  are 
two  digestive  substances  made  by  the  gastric  glands.  The  gas- 
These  are  pepsin  and  rennin,  and  are  called  ferments.  tric  Juice 
The  principal  work  done  in  the  stomach  is  to  liquefy  the  food. 


KEEPING  THE  BODY  IN  HEALTH 


The  rennin  in  the  gastric  juice  has  an  interesting  work  to  per- 
form in  connection  with  the  digestion  of  milk.  If  milk  were  to 
remain  in  the  liquid  form  in  which  it  is  swallowed,  it  would 
pass  quickly  out  of  the  stomach  without  digestion.  The  rennin 
changes  the  milk  into  curds,  so  that  the  proteins  which  it  contains 

can  then  be  acted  upon  by  the 
pepsin.  If  the  curds  are  hard  and 
tough,  the  work  will  be  harder 
and  the  milk  will  not  be  so  well 
digested.  For  this  reason  it  is 
not  a  good  thing  to  swallow  milk 
rapidly,  in  large  quantities,  as  one 
does  water.  A  nursing  babe  takes 
the  milk  in  small  quantities.  The 
natural  method  of  drinking  milk 
is  to  take  it  in  small  sips,  so  that 
it  can  form  small  curds,  which  can 
easily  be  acted  upon  by  the  gastric 
juice. 

The  flow  of  the  gastric  juice  is, 
like  that  of  the  saliva,  regulated 
in  a  most  exact  manner,  both  in 
THE  JUICE  THAT  is  POURED  OUT  ON  THE   quantity  and  quality,  to  suit  the 

FOOD    IN    THE    STOMACH    IS    MADE     IN      r          ,          ,  T-         J 

GASTRIC  GLANDS,  LIKE  THE  ONE  SHOWN  *°ods  that  are  eaten.     *  oods  con- 
IN  THE  PICTURE;  THESE  ARE  FOUND  IN  taining  a  large  amount  of  protein 

THE  LINING  OF  THE  STOMACH.  °  J 

call   forth   an   abundant    flow  of 

gastric  juice,  whereas  starchy  and  fatty  substances,  which  are 
not  digested  in  the  stomach,  do  not  excite  the  gastric  glands 
to  lively  activity. 

The  pepsin  alone  cannot  digest  protein,  since  it  requires  an 
acid  to  make  it  active.  Some  of  the  gastric  glands  pour  out  a 
strong  acid  called  hydrochloric  acid.  When  the  food  becomes 


HOW  FOOD  BECOMES  LIVING  TISSUE 


thoroughly  mixed  with  the  gastric  juice,  as  is  the  case  about  an 
hour  after  it  enters  the  stomach,  the  digestion  of  the  starch,  which 
has  been  going  on  up  to  that  time,  ceases.  The  acid  in  the  gas- 
tric juice  also  does  the  important  work  of  destroying  bacteria  or 
germs  that  get  into  the  stomach  through  the  mouth.  So  the 
stomach  is  a  kind  of  disinfecting  room  for  protecting  the  body 
against  germs. 

Next  to   the  lining  membrane,   which  contains   the  gastric 
glands,   is   a   coat  of  muscular   tissue.     By   contracting   these 
muscles,  the  stomach  is  able  to  change  its  size  and  Kneading 
shape  and  to  produce  a  sort  of  kneading  action  upon  the  fo°d 
the  food,  thus  soft- 


ening it  and  thor- 
oughly mingling  it 
with  the  gastric 
juice.  This  work 
is  kept  up  until  the 
whole  mass  is  soft 
and  is  something 
like  a  thick  soup. 

The  food  begins 
passing  from  the 
stomach  within  a 
few  minutes  after 
eating  begins.  At 
brief  intervals  the 
pylorus  opens  ana 
passes  out  a  small 

amount    Of    the  di-     THE  SMALL  INTESTINE  is  A  VERY  ACTIVE   LABORATORY  FOR 

A  V         'A    f        ^  DIGESTION.      THE  COLON,  OF  WHICH  YOU  CAN  GET  A  GLIMPSE 

gested  liquid  lOOd  J         IN  THE  PICTURE,  is  A  RECEPTACLE  FOR  WASTE  AND  FOR 
and   at   the  end  Of         PORTIONS  OF  FOOD  THAT  CANNOT  BE  USED. 

four  or  five  hours  the  stomach  is  completely  emptied. 


/nfest/ne 


Co/on 


32  KEEPING  THE  BODY  IN  HEALTH 

When  the  food  passes  through  the  pylorus,  it  enters  the  next 
and  most  important  of  the  digestive  organs,  the  small  intestine, 
which  is  the  third  food  station.  This  small  intestine  is  a  slender 
tube,  about  twenty  feet  long,  that  passes  from  the  stomach  to 
the  large  intestine  or  colon.  You  can  see  in  the  illustration 
on  page  31  the  curious  way  in  which  this  long  tube  is  coiled 
and  packed  in  the  part  of  the  body  it  occupies.  The  contact  of 
the  acid  liquid  with  the  mucous  lining  of  the  intestine  causes 
the  pylorus  to  close.  The  pylorus  remains  closed  until  the  acid 
liquid  from  the  stomach  is  neutralized  by  the  alkaline  bile  and 
pancreatic  juice. 

We  have  already  studied  the  work  of  two  of  the  five  digestive 
fluids.  The  three  remaining  juices  are  poured  upon  the  food 
while  it  is  in  the  small  intestine. 

Digestion         ^ne  °*  t^iese  *s  Poured  out  by  the  intestine  itself  and 
in  the  is  called  intestinal  juice.     The  other  two  are  secreted 

small  by  two  large  organs  lying  near  the  stomach,  the  liver 

intestine        and  ^  pancreas> 

The  fluid  prepared  by  the  liver  is  called  bile  and  is  stored 
up  in  a  sack  or  pouch  called  the  gall  bladder.  When  needed  for 
the  work  of  digestion-,  the  bile  is  poured  through  a  duct  into  the 
small  intestine,  in  much  the  same  way  that  the  saliva  is  poured 
out  into  the  mouth.  The  duct  enters  the  intestine  a  few  inches 
below  the  stomach. 

Up  to  this  point  in  the  work  of  digestion,  the  starch  has  been 
acted  upon  by  the  saliva,  and  the  proteins  by  the  gastric  juice ; 
but  no  change  has  taken  place  in  the  fats,  except  that  they  have 
been  melted  by  the  heat  of  the  body.  The  special  work  of  the 
bile  is  to  aid  in  the  digestion  of  the  fats.  Fats  are  first  emul- 
sified, or  subdivided  into  particles  so  small  that  they  may  be 
absorbed.  An  emulsion  may  be  made  experimentally  by  mix- 
ing olive  oil  with  a  quantity  of  gum  water.  Add  three  or  four 


HOW  FOOD  BECOMES  LIVING  TISSUE  33 

parts  of  water  to  one  part  of  mucilage,  shake  until  well  mixed, 
and  then  add  one  part  of  oil.  Note  that  when  the  oil  is  first 
added  the  two  liquids  remain  distinct.  Shake  the  mixture 
thoroughly  for  a  minute  ;  it  will  then  be  impossible  to  distinguish 
the  oil  from  the  gum  water.  The  result  will  be  a  creamy  liquid, 
which,  added  to  water,  produces  a  mixture  having  a  milky  ap- 
pearance. If  allowed  to  stand  for  a  while,  the  emulsion  will  rise 
to  the  top  as  cream  rises  upon  milk. 

Next  the  fats  are  changed  into  soaps  by  combining  with  the 
alkaline  substances  of  the  bile  and  pancreatic  juice.  In  the  form 
of  soaps,  the  fats  are  soluble  and  can  be  absorbed.  After  ab- 
sorption, the  soaps  are  changed  back  into  fats. 

The  pancreatic  juice  is  formed  by  a  gland  called  the  pancreas 
which  is  located  near  the  opening  of  the  small  intestine.  The 
remarkable  thing  about  the  pancreatic  juice  is  that  it  does  the 
work  of  all  the  other  juices  combined.  It  digests  starch,  like 
the  saliva;  it  digests  proteins,  like  the  gastric  juice;  and  it 
acts  upon  fats,  as  does  the  bile.  Why  should  there  be  this 
arrangement  in  the  food  canal,  do  you  think? 

The  powerful  pancreatic  jui-ce  is  poured  out  near  the  entrance 
to  the  small  intestine,  so  that  the  digestive  work  to  be  done 
there  is  well  started.  The  intestinal  juice,  which  is  poured  out 
along  the  whole  twenty  feet  of  the  intestine  and  does  much  the 
same  kind  of  work  as  the  pancreatic  juice,  completes  the  work 
started  by  the  pancreatic  juice.  In  addition  to  this,  the  intes- 
tinal juice  has  the  power  of  digesting  cane  sugar,  which  is  the 
only  kind  of  sugar  that  needs  digestion. 

While  this  important  work  of  digestion  is  taking  place  in  the 
small  intestine,  another  interesting  work  of  equal  importance  is 
being  carried  on  there.  If  we  examine  the  mucous  membrane 
lining  of  the  small  intestine,  we  find  that  it  contains,  like  the 
stomach,  the  little  tubelike  glands  that  make  the  digestive  fluid, 


34 


KEEPING  THE  BODY  IN  HEALTH 


and  in  addition  to  these  a  thick  covering  with  tiny  fingerlike 
projections  which  give  it  a  velvety  appearance.  These  villi y  as 
they  are  called,  have  a  very  important  work  to  do.  They  suck 
up  the  digested  food,  much  as  the  tiny  rootlets  of  a  plant  suck 
up  its  nourishment  from  the  soil.  Indeed,  the  villi  may  be 
properly  regarded  as  the  "roots"  of  the  body,  while  the  liquid 

food  which  bathes  the  villi  is  the 
"soil"  out  of  which  the  body  draws 
its  sustenance  just  as  a  tree  or 
plant  extracts  substances  for  its 
growth  out  of  the  earth. 

We  have  already  learned  that 
all  the  digested  food  must  be  ab- 
sorbed through  the  walls  of  the 
alimentary  canal.  The  absorbing 
surface  of  the  small  intestine,  where 
this  work  of  absorption  chiefly  takes 
place,  is  very  greatly  increased  by 
the  villi  and  by  folds  in  the  lining 
membrane.  The  length  of  the 
small  intestine  is  about  twenty  feet, 
and  its  circumference  about  three 
inches,  dimensions  which  would 
give  an  absorbing  surface  of  about 
five  square  feet.  By  the  villi  and  the  folds  in  the  mucous 
membrane  it  is  increased  more  than  fivefold.  There  are 
5,000,000  villi.  Each  one  of  the  villi  absorbs  about  two  table- 
spoonfuls  of  liquid  in  the  course  of  a  lifetime  of  sixty  or  seventy 
years.  Try  to  figure  out,  in  terms  of  quarts,  the  total  amount 
of  liquid  absorbed  by  all  the  villi  during  the  course  of  a  lifetime. 
The  work  of  digestion  and  absorption  going  on  in  the  small 
intestine  is  greatly  helped  by  the  muscles,  as  we  have  found  to 


THE  VILLI  LINE  THE  INTERIOR  OF  THE 
SMALL  INTESTINE  AND  ABSORB  THE 
FOOD  WHEN  IT  IS  FULLY  DIGESTED. 

THERE   ARE   5.000,000    VILLI,   AND 
YOU  CAN  SEE  THAT  TAKEN  TOGETHER 

THEY    HAVE  AN    ENORMOUS  ABSORB- 
ING SURFACE. 


HOW  FOOD  BECOMES  LIVING  TISSUE  35 

be  the  case  in  the  work  of  the  mouth  and  stomach.  Like  the 
stomach,  the  intestine  has  a  coat  of  muscular  tissue  next  to  the 
mucous  membrane.  By  the  work  of  these  muscles,  the  food  is 
kept  in  constant  motion,  so  that  it  becomes  thoroughly  mixed 
with  the  digestive  juices,  and  the  villi  dip  into  all  parts  of  it  to 
suck  up  the  digested  portion.  From  the  stomach  downward,  the 
food  is  moved  along  the  alimentary  canal  by  successive  contrac- 
tions of  the  muscular  walls  of  the  intestines.  These  contractions 
are  known  as  peristaltic  movements,  and  they  occur  with  great 
regularity  during  digestion. 

Here  is  an  experiment  which  will  give  an  idea  as  to  how 
the  food  is  moved  along  the  intestine :  Fill  a  rubber  tube  with 
water.  By  pinching  the  tube,  the  water  may  be  made  to 
move  along  in  it.  The  peristaltic  action  or  contraction  of  the 
intestine  in  a  similar  way  pushes  the  food  along. 

The  indigestible  materials  in  the  food,  as  well  as  the  wastes 
formed  during  digestion  and  any  of  the  digested  food  that  still 
remains,  is  carried  from  the  small  intestine  into  the  The  last 
large  intestine,  which  is  not  a  digestive  organ  but  food 
simply  a  reservoir  for  refuse,  or  a  waste  receptacle,  station 
in  which  the  food  residue  is  retained  for  a  short  time  before 
being  ejected  from  the  body.     As  the  liquid  food  is  absorbed t 
the   residue    becomes   more    and    more   solid,   and  with   other 
wastes  is  moved  forward  and  finally  discharged  from  the  body. 

To  prevent  the  wastes  and  food  residues  from  passing  back 
into  the  small  intestine  after  they  have  been  pushed  into  the 
colon,  nature  has  provided  at  the  end  of  the  small  intestine  a 
check  valve  known  as  the  ileoc&cal  valve.  This  valve  behaves 
very  much  like  the  pylorus.  It  passes  the  food  residues  and 
wastes  into  the  colon  and  then  prevents  their  return  to  the 
small  intestine.  Sometimes  this  valve  becomes  damaged,  and 
then  the  waste  from  the  colon  passes  back  into  the  small  intes- 


KEEPING  THE  BODY  IN  HEALTH 


tine,  and  great  harm  results.  The  tongue  ie  likely  to  become 
coated,  the  breath  becomes  bad,  the  appetite  is  lost,  the  head 
aches,  and  the  patient  often  says  that  he  is  "  bilious,"  think- 
ing that  his  liver  is  not  so  active  as  it  should  be ;  whereas,  the 
real  trouble  is  that  such  a  large  quantity  of  waste  matter  is 
absorbed  into  the  blood  that  the  liver  has  more  work  than  it 
can  do  and  becomes  exhausted  in  its  efforts  to  destroy  all  the 
poisons  which  are  brought  to  it  from  the  intestine.  Why 

should  the  breath  become  tainted,  the 
appetite  be  lost,  and  the  head  ache 
when  poisons  are  absorbed  into  the 
blood  in  large  quantities? 

If  the  work  of  digestion  has  been 
well  done,  these  wastes  and  food  resi- 
dues will  pass  naturally  out  of  the 
body  at  regular  intervals.  The  empty- 
ing of  the  colon  takes  place  normally 
after  each  meal.  It  is  very  easy  to 
form  habits  in  this  respect  and  of 
great  importance  that  the  habits  we 
form  should  be  good  ones.  It  is  just 

THIS  PICTURE,  MADE  FROM  AN  X-RAY  m  j.       i 

PHOTOGRAPH,  SHOWS  THE  LocA-  as  important  to  discharge  the  waste 
TION  OF  THE  COLON.  products  from  the  body  as  it  is  to 

take  in  a  fresh  supply  of  food.  If  the  drains  of  a  city  become 
.choked  up,  the  health  of  the  community  is  very  likely  to  suffer. 
The  health  of  the  cell  communities  which  form  the  human  body 
likewise  depend  upon  the  prompt  removal  of  all  wastes. 

Besides  the  changes  which  are  made  in  the  food  in  the  intes- 
The  tines  by  the  digestive  juices,  there  are  other  changes 

work  of  which  are  produced  by  microbes.  We  saw  that  the 
microbes  acjj  gastric  juice  destroyed  the  germs  that  found 
entrance  to  the  healthy  stomach.  The  intestinal  juices  are 


HOW  FOOD  BECOMES  LIVING  TISSUE  37 

not  acid,  so  harmful  germs  have  a  chance  to  grow  and  multiply 
in  the  intestines.  The  microbes  gradually  increase  in  number 
from  the  stomach  to  the  large  intestine,  which  is  a  very  favor- 
able breeding  place  for  germ  colonies.  Some  of  these  are  not 
only  harmless,  but  even  friendly  and  useful.  Others,  however, 
cause  the  contents  of  the  intestine  to  decay  and  to  give  off  very 
offensive  odors  and  poisonous  products  that  are  most  injurious 
to  the  cells.  In  a  person  who  is  in  perfect  health  and  who  lives 
wholesomely,  these  poison  forming  germs  are  not  present  in 
sufficient  numbers  to  do  harm.  But  under  certain  conditions, 
especially  in  the  case  of  one  who  lives  unhealthfully,  they  may 
multiply  to  a  very  great  extent,  and  the  poisons  they  produce 
may  be  a  cause  of  serious  disease. 

In  all  cases,  the  prompt  removal  of  the  waste  matters  in  the 
intestine  is  a  matter  of  great  importance.  Headaches  and 
general  bad  feelings  and  bad  temper  may  result  from  the  body's 
being  poisoned  by  the  waste  matters  that  have  been  allowed 
to  remain  in  it  beyond  the  natural  time.  The  result  is  that 
the  harmful  germs  have  an  opportunity  to  get  a  great  start. 
They  grow  rapidly  and  the  contents  of  the  colon  become  highly 
putrid.  Gases  and  various  poisons  are  formed  which  are  ab- 
sorbed into  the  blood  and  give  the  liver  and  the  kidneys  extra 
work  to  do.  Some  of  these  poisons  find  their  way  out  through 
the  lungs  and  cause  a  bad  breath.  All  the  tissues  of  the  body 
become  tainted  with  the  poisons.  This  is  auto-intoxication. 
Putrefaction  in  the  colon  is  more  active  in  the  cases  of  those 
who  eat  heartily  of  meat  and  eggs. 

The  digested  food  which  is  absorbed  by  the  walls  of  the  ali- 
mentary canal,  in  much  the  same  way  that  a  sponge  absorbs 
water,  is,  in  the  process  of  absorption,  changed  into  blood.  It 
then  passes  into  the  blood  vessels  with  which  the  walls  of  the 
canal  are  richly  supplied. 


KEEPING  THE  BODY  IN  HEALTH 


On  the  right  side  of  the  body,  just  outside  the  alimentary 
canal,  tucked  snugly  away  in  a  corner  by  itself  beneath  the 
A  wonder-  diaphragm,  is  the  liver.  The  liver  is  the  largest 
ful  labora-  gland  in  the  body,  weighing  in  a  man  of  average  size 
tory  —  about  three  and  a  half  pounds. 

In  some  respects  the  liver  is  the  most  wonderful 
organ  in  the  body.     It  serves  the  body  in  more  ways  than  any 


ffepat/c  Duct       ffepatic  Artery 


Gaf/-B/ac/der 


Umb/'/icaf 


Porfa/  Ife/rt1  V/ifer/or 

THE  LOWER  SURFACE  OF  THE  LIVER.      THE  GALL  BLADDER  ADJOINS  IT.      THE   LIVER   IS  WELL 
SUPPLIED    WITH    ARTERIES   AND   VEINS.       WHY? 

other  organ,  performing  at  least  twenty  different  kinds  of  work. 
We  will  mention  some  of  its  tasks. 

Before  the  food  supply  in  the  blood  passes  to  the  heart,  from 
which  it  is  to  be  distributed  to  the  body  for  the  use  of  the  cells, 
it  passes  to  the  liver  for  final  inspection  and  preparation.  The 
starch,  which  during  digestion  was  converted  into  sugar,  is 
changed  back  by  the  liver  into  a  kind  of  animal  starch  called 
glycogen.  In  this  form  it  is  stored  up  in  the  tissues  of  the  liver 


HOW  FOOD  BECOMES  LIVING  TISSUE  39 

until  it  is  needed  for  body  work  or  heat  production,  when  it  is 
given  out  as  needed,  having  been  first  changed  back  into  sugar. 
In  this  respect,  the  liver  might  be  looked  upon  as  a  sort  of  liv- 
ing, automatic  stoker,  which  supplies  fuel  to  the  body  as  needed, 
just  as  devices  made  for  the  purpose  supply  coal,  as  needed,  to 
the  furnaces  of  steam  boilers. 

The  liver  also  acts  as  a  kind  of  food  inspector  for  the  purpose 
of  protecting  the  body  against  poisons.  When  any  metallic 
poison  such  as  mercury,  lead,  or  arsenic  is  taken  into  the  blood, 
the  liver  absorbs  and  retains  as  much  as  possible  of  the  poison 
and  so  protects  the  rest  of  the  body.  Vegetable  and  animal 
poisons  are  also  destroyed  by  the  liver. 

The  liver  stores  up  the  vitamines  which  are  necessary  for 
growth.  These  vitamines  are  found  mainly  in  milk  and  in  the 
green  parts  of  plants.  They  are  almost  entirely  absent  from 
seeds,  roots,  and  meats. 

This  storing  up  of  vitamines  by  the  liver  is  especially  valuable 
for  young  animals  and  for  growing  boys  and  girls.  In  this  way, 
the  process  of  growth  will  not  be  checked  if  for  a  day  or  two 
one  happens  to  eat  food  lacking  in  growth-promoting  vitamines. 
When  these  vitamines  are  wholly  absent  from  the  food  for  a 
long  time,  an  animal  not  only  ceases  to  grow  but  its  eyes  ulcerate, 
and  it  soon  becomes  blind.  The  Eskimos  and  other  people  who 
live  largely  upon  meat  are  compelled  to  eat  the  livers  of  seal 
and  other  animals  to  obtain  the  necessary  supply  of  vitamines. 
Plants  are  the  original  source  of  vitamines.  Spinach  and 
other  green  stuffs  and  cows'  milk  furnish  them  in  abundant 
quantity. 

Do  you  not  think  we  are  fortunate  in  living  in  a  country  in 
which  we  can  obtain  an  abundance  of  good  foods  containing 
vitamines,  so  that  we  are  not  obliged  to  eat  the  livers  of  animals 
to  obtain  them? 


40  KEEPING  THE  BODY  IN  HEALTH 

Another  highly  essential  function  of  the  liver  is  the  making  of 
bile.  About  twenty  ounces  of  this  important  fluid  is  made  daily 
by  the  liver  and  poured  into  the  intestine  just  below  the  stomach. 
A  portion  is  kept  stored  up  in  the  gall  bladder  ready  for  im- 
mediate use  when  needed.  Sometimes,  through  wrong  diet  and 
neglect  to  keep  the  colon  free  from  refuse,  the  gall  bladder  be- 
comes infected  and  gallstones  are  formed,  a  condition  which  is 
often  accompanied  by  very  great  pain  and  may  require  a  serious 
operation  for  its  relief. 

The  bile  does  many  useful  things,  of  which  the  most  impor- 
tant are  these: 

(1)  It  carries  off  the  alkaline  wastes  of  the  body,  which  are 
highly  poisonous  and  hence  must  be  promptly  gotten  rid  of. 

(2)  It  helps  to  neutralize  the  acid  liquids  which  come  from 
the  stomach  and  which  would,  otherwise,  injure  the  membrane 
lining  the  small  intestine. 

(3)  It  aids  the  pancreatic  juice  in  the  digestion  of  food. 

(4)  It  aids  absorption. 

(5)  It  hinders  the  growth  of  germs  in  the  intestine. 

You  can  well  understand,  therefore,  how  important  it  is  to  keep 
the  liver  in  good  health,  and  not  to  make  it  work  so  hard  in 
destroying  poisons  and  removing  wastes  from  the  body,  that  it 
will  become  overtaxed  and  refuse  to  perform  its  duties.  You 
can  understand  also  why  people  become  seriously  sick  when 
the  liver  gets  out  of  order.  What  do  you  think  would  be  the 
best  way  or  ways  to  keep  the  liver  in  good  working  order? 

We  should  mention  here  that  not  all  the  food  supply  passes 
through  the  liver  on  its  way  to  the  heart.  A  comparatively 
small  portion,  especially  that  which  contains  the  digested  fats, 
is  taken  from  the  intestines  by  small  vessels  called  lacteals,  which 
carry  it  to  a  duct  called  the  thoracic  duct,  by  which  it  is  carried 
directly  to  the  heart. 


HOW  FOOD  BECOMES  LIVING  TISSUE  41 

The  final  act  in  the  nourishment  of  the  body  is  the  making 
of  the  liquid  blood  into  solid  tissues,  a  change  exactly  the  reverse 
of  that  which  takes  place  in  digestion.     Each  kind  of  Making 
tissue  takes  from  the  blood  the  material  needed  for  its  blood  into 
own  uses  and  builds  and  repairs  itself.     So  you  see  t*881168 
that  assimilation,  for  that  is  what  this  process  is  called,  is  some- 
thing like  creation.     It  is  the  building  of  tissues  and  organs 
out  of  the  blood,  which  forms  the  stream  of  life.     The  blood, 
in  fact,  is  a  sort  of  traveling  market,  circulating  through  the 
blood  vessels  as  through  canals,  and  from  it  the  nutritive  ele- 
ments prepared  in  the  digestive  organs  are  secured  by  the  tissues 
wherever  they  are  needed. 

Let  us  now  retrace  briefly  the  chain  of  events  which  follow 
each  other  in  the  work  of  digestion,  from  the  time  the  food  enters 
the  body  until  it  becomes  a  part  of  it, — built  into  its  living  tissue. 

In  the  mouth  the  food  is  ground  and  crushed  into  a  pulp  and 
thoroughly  moistened  with  saliva,  which  begins  the  digestion 
of  starch. 

It  then  passes  through  the  esophagus  into  the  stomach,  which 
is  a  sort  of  storehouse  or  preparatory  chamber,  and  the  work 
of  protein  digestion  begins. 

Having  been  thoroughly  worked  upon  by  the  gastric  juice 
and  the  stomach  muscles,  it  is  passed  out  through  the  pylorus 
into  the  small  intestine.  Here  the  bile  formed  in  the  liver  is 
poured  upon  it  for  the  digestion  of  fats.  The  pancreas  also 
contributes  its  powerful  juice,  which  works  upon  all  three  classes 
of  foods,  —  starches,  fats,  and  proteins.  The  intestinal  juice 
does  much  the  same  work  as  the  pancreatic  juice,  and  in  addi- 
tion it  digests  cane  sugar. 

As  the  digested  food  is  worked  upon  and  carried  along  by  the 
muscles  to  the  large  intestine,  it  is  absorbed  by  means  of  the 
villi  lining  the  intestinal  wall.  In  the  large  intestine  the  ab- 


42  KEEPING  THE  BODY  IN  HEALTH 

sorption  of  the  digested  food  is  completed  and  the  waste  matters 
are  discharged  from  the  body. 

The  absorbed  food  is  carried  by  the  blood  vessels  to  the  liver, 
which  completes  the  work  of  digesting  the  proteins  or  building 
foods,  and  regulates  the  supply  of  fuel  foods  to  the  body,  storing 
up  digested  starch  in  the  form  of  glyoogen.  The  liver  also  ex- 
tracts poisons  and  changes  them  into  less  harmful  substances. 

The  food  supply  then  passes  to  the  heart,  from  which  it  is 
sent  out  into  every  part  of  the  body  to  be  used  by  the  cells  for 
the  building  up  of  the  living  tissues  and  organs  which  compose 
the  body. 

HEALTH  PROBLEMS 

1.  Mention  at  least  five  insoluble  articles  that  can  be  digested,  and 
explain  how  digestion  is  possible. 

2.  Which  of  your  permanent  teeth  have  you  now?    Which  of  your 
baby  teeth  are  you  losing  ?    What  permanent  teeth  must  you  still  get  ? 

3.  Just  where  on  the  tongue  are  the  taste  buds  situated?     What  effect 
would  it  have  on  a  person  if  his  taste  buds  should  be  destroyed? 

4.  Have  you  ever  had  a  sickness  during  which  your  mouth  seemed 
"dry"  so  that  you  could  not  moisten  your  food  well?    How  did  the  food 
taste?     Explain. 

5.  Do  people  who  masticate  their  food  thoroughly  get  more  pleasure 
from  it  than  those  who  swallow  it  in  a  hall-masticated  condition?     Explain. 

6.  Have  you  ever  noticed  that  when  you  are  sick  food  will  not  make 
your  mouth  "water"?    What  is  the  explanation  of  this? 

7.  Do  you  know  why  people  often  crave  acid  drinks,  such  as  lemonade 
and  the  like?    Would  you  expect  these  to  assist  digestion?    Why? 

8.  Write  a  little  story  about  "What  Happens  to  a  Mouthful  of  Bread." 
Show  what  interesting  things  occur  until  the  body  is  finished  with  the 
bread. 

REVIEW  QUESTIONS 

1.  What  work  is  necessary  in  order  to  prepare  nutrients  so  that  they 
can  be  used  by  the  cells  as  food? 

2.  Compare  the  organs  used  in  digestion  with  the  workers  in  a  bakery 
establishment. 


HOW  FOOD  BECOMES  LIVING  TISSUE  43 

3.  What  is  the  name  of  the  canal  through  which  the  food  passes? 
What  are  its  principal  parts  ? 

4.  What  are  the  digestive  juices?    How  many  kinds  are  there? 

5.  Of  what  does  the  work  of  digestion  consist? 

6.  Why  is  mastication  necessary? 

7.  How  many  teeth  does  an  adult  have?    Describe  each  kind  and  tell 
its  use. 

8.  What  is  the  saliva,  where  is  it  formed,  and  what  is  its  use?    What 
is  necessary  in  order  that  saliva  may  get  in  touch  with  one's  food? 

9.  What  are  the  ferments  and  for  what  are  they  used  in  the  body? 

10.  If  one  has  masticated  his  food  poorly,  will  he  have  to  make  an  effort 
to  swallow  it  ?     Why  ? 

11.  What  is  the  pylorus ?    Describe  its  work. 

12.  Describe  the  "signal  system"  which  nature  has  provided  in  the 
body  to  help  digestion. 

13.  What  happens  in  the  mouth  when  one  sees  or  smells  appetizing 
food?     How  does  this  help  digestion? 

14.  What  juice  is  mixed  with  the  food  in  the  stomach? 

15.  Suppose  you  should  examine  the  lining  membrane  of  the  stomach, 
what  would  you  see  ? 

16.  How  is  the  amount  ot  gastric  juice  prepared  in  the  stomach  adapted 
to  the  needs  of  digestion?     What  is  the  use  of  this  acid? 

17.  Describe  the  muscular  action  of  the  stomach.     How  does  this  help 
digestion  ? 

1 8.  How  long  does  it  take  ordinarily  for  a  meal  to  pass  out  of  the  stomach  ? 

19.  Where  is  the  small  intestine?    How  many  juices  are  poured  out  on 
the  food  from  the  intestine  ? 

20.  What  organ  makes  the  bile  ? 

21.  Where  and  how  are  the  fats  of  our  food  digested? 

22.  What  is  the  pancreatic  juice?     What  foods  will  it  digest? 

23.  Describe  the  villi  in  the  mucous  membrane  of  the  small  intestine. 
What  is  their  duty? 

24.  What  is  the  large  intestine?    How  does  it  differ  from  the  small  in- 
testine in  its  work  ? 

25.  Before  the  food  in  the  blood  passes  to  the  heart,  where  must  it  go 
for  final  inspection  ? 

26.  Just  what  does  the  liver  do  to  the  food  to  make  it  ready  for  use  by 
the  cells?    Why  is  it  right  to  speak  of  the  liver  as  a  kind  of  food  inspector? 


CHAPTER  IV 

EATING  FOR  HEALTH  AND  PLEASURE 

THE  only  part  of  the  important  work  of  nutrition  that  Nature 
has  left  to  us  is  the  selection  of  the  food,  and  the  preparation  of 
it  for  digestion  by  thorough  chewing.  All  the  rest  of  the  work 
is  done  for  us  without  any  thought  or  effort  on  our  part.  Every- 
thing done  in  the  process  of  digestion,  however,  is  greatly  in- 
fluenced by  the  manner  in  which  we  do  our  part  of  the  work. 

As  an  aid  to  us  in  selecting  the  food  and  as  an  inducement 
to  us  to  keep  it  in  the  mouth  until  our  part  of  the  work  is  well 
done,  Nature  has  put  into  it  many  kinds  of  agreeable  flavors. 
When  we  swallow  our  foods  with  little  or  no  chewing,  we  lose 
these  flavors  and  miss  the  pleasure  that  Nature  intended  for  us 
in  eating. 

One  of  Professor  Pavlov's  interesting  experiments  proved 
that  the  amount  and  efficiency  of  the  gastric  juice  depend  very 
much  upon  the  enjoyment  of  the  food.  The  esophagus  of  a  dog 
was  divided  and  part  of  it  connected  with  a  tube.  When  the 
dog  was  fed,  the  food,  instead  of  passing  into  the  stomach, 
dropped  out  through  the  opening  into  a  dish.  The  dog,  how- 
D.  ever,  thought  he  was  having  a  good  meal,  and  the 

tion  de-  gastric  juice  immediately  began  to  form  in  the  stomach 
pends  upon  and  continued  to  pour  out  as  long  as  he  kept  on  eat- 
e?ioy*?ent  ing  and  enjoying  the  food.  When  he  was  given  food 
that  he  did  not  like,  however,  there  was  no  outpouring 
of  gastric  juice.  Also  when  food  was  put  into  the  dog's  stomach 
through  the  opening,  without  his  knowledge,  little  gastric  juice 
was  formed  and  the  food  lay  there  for  hours  undigested. 

44 


EATING  FOR  HEALTH  AND   PLEASURE  45 

The  gastric  juice  that  is  poured  out  at  the  beginning  of  diges- 
tion, as  the  result  of  the  enjoyment  of  the  food,  has  been  given 
the  name  "appetite  juice,"  and  has  been  found  to  be  the  most 
powerful  and  active  juice  formed  in  the  stomach.  We  can  see 
from  this  that  the  more  the  food  is  enjoyed  the  better  it  will  be 
digested.  If  a  person  is  not  hungry,  he  does  not  relish  his  food ; 
and  for  that  reason  he  will  have  no  " appetite  juice"  to  welcome 
the  food  to  the  stomach  and  to  begin  the  digestive  process. 

Those  who  wish  to  keep  the  body  in  the  best  state  of  health 
should  cultivate  the  habit  of  chewing  the  food  until  all  the 
soluble  parts  have  been  dissolved.  As  a  rule,  this  will  be  until 
enough  saliva  has  been  poured  out  to  extract  from  the  food  all 
the  substances  having  any  taste.  In  other  words,  we  should 
chew  the  food  until  there  is  no  taste  left  in  it. 

Bolting  or  swallowing  food  without  proper  attention  to  mas- 
tication is  a  very  injurious  though  common  habit.     Many  of 
Us  are  in  such  a  hurry  that  we  prefer  to  make  use  of  gome 
soft  foods  of  some  sort  that  can  be  easily  swallowed  causes  of 
without  chewing.     Moist  foods  such  as  mushes  and   indigestion 
soups  cause  the  flow  of  only  a  small  part  of  the  saliva  that  is 
called  forth  by  the  same  food  in  a  dry  state.     It  is  therefore 
better  that  much  of  our  food  should  be  taken  dry  so   as  to 
compel  thorough  mastication. 

It  should  be  remembered,  however,  that  in  taking  starchy 
foods  which  are  already  moist,  mastication  is  also  very  neces- 
sary for  the  development  of  the  amount  of  saliva  required  for 
the  digestion  of  the  starch.  Even  such  liquid  foods  as  vegetable 
soups  or  gruels  should  be  held  in  the  mouth  until  thoroughly 
mingled  with  the  saliva.  In  the  feeding  of  horses,  farmers  recog- 
nize the  value  of  thorough  mastication.  To  secure  this,  they 
frequently  put  a  quantity  of  pebbles  into  the  manger  along 
with  the  food.  The  animal  is  thus  compelled  to  take  the  food 


KEEPING  THE  BODY  IN  HEALTH 


Pyloru. 


into  its  mouth  in  such  small  quantities  that  hasty  eating  is 
prevented. 

Drinking  at  meals  usually  leads  to  the  bolting  of  food.  These 
two  evils  are  closely  connected.  Liquids  taken  with  the  food  dimin- 
ish the  flow  of  saliva 
and  so  interfere  with 
the  work  of  digestion. 
Very  cold  liquids  are 
especially  bad,  be- 
cause they  lower  the 
temperature  of  the 
stomach  and  thus  put 
a  stop  to  the  diges- 
tive process.  A  tem- 
perature of  100  de- 
grees is  required  for 
digestion.  It  has  been 
observed  that  a  glass- 
ful of  ice  water  low- 
ered the  temperature 
of  the  stomach  con- 
tents to  70  degrees 
and  that  more  than 
half  an  hour  passed 
before  the  normal 
temperature  was  re- 
gained. Hence  the 
whole  digestive  proc- 
ess was  checked  for  half  an  hour. 

Hot  drinks,  while  they  excite  the  stomach  temporarily,  tend 
to  relax  and  weaken  its  muscles  and  lessen  digestive  vigor. 
They  also  destroy  certain  useful  elements  in  the  saliva.  The 


THESE  OUTLINES  SHOW  CHANGES  IN  THE  SHAPE  OF  THE 
STOMACH  DURING  DIGESTION,  AS  CAUGHT  BY  THE  X-RAY. 


EATING  FOR  HEALTH  AND  PLEASURE  47 

highest  degree  of  digestive  activity  seems  to  be  secured  by  the 
use  of  food  at  a  temperature  a  little  below  that  of  the  body, 
or  at  its  ordinary  temperature. 

The  best  time  to  take  liquids  is  at  the  close  of  the  meal,  when 
there  will  be  little  danger  of  drinking  too  much.  Fruits  eaten 
with  the  meal,  or  at  the  close,  lessen  the  necessity  of  drinking 
at  meals.  It  is  not  well  to  try  to  get  along  without  any  liquids 
when  we  eat  a  meal  of  solid  food.  Experiments  have  shown 
clearly  that  a  glassful  of  water,  not  too  cold,  taken  with  the 
meal,  helps  digestion  and  enables  one  to  get  more  good  from  his 
food.  A  wise  plan  is  to  take  a  glassful  of  cool  water  a  half 
hour  before  a  meal,  and  a  glassful  may  be  sipped  at  intervals 
during  the  meal. 

A  variety  of  food  is  necessary  to  assist  the  appetite,  upon 
which  good  digestion  so  largely  depends.  It  is,  therefore,  im- 
portant that  the  food  should  be  varied  from  day  to  day  or  at 
different  meals,  as  each  food  supplies  the  body  with  some 
special  useful  product.  The  stomach,  however,  may  easily  be 
overworked  by  a  great  variety  of  foods  taken  at  a  single  meal. 

Simplicity  in  one's  selection  of  food  is  very  important  for  good 
digestion.  The  natural  appetite  is  easily  satisfied  with  a  small 
number  of  foods,  simply  and  wholesomely  prepared.  Animals 
such  as  the  sheep,  the  goat,  and  the  cow,  which  in  the  course 
of  a  morning's  grazing  may  swallow  one  hundred  different  kinds 
of  herbs,  have  very  complicated  stomachs  with  four  compart- 
ments. Certain  fishes  which  live  on  other  fish  are  provided 
with  as  many  as  half  a  dozen  stomachs  in  which  to  do  their  diges- 
tive work.  Man,  with  a  single,  simple  stomach,  often  sits  down 
to  a  feast  which  would  tax  the  digestive  power  of  an  animal 
having  many  stomachs. 

The  digestion  of  a  meal  in  the  stomach  requires  about  four 
hours.  As  you  might  expect,  the  stomach  then  needs  a  period 


48  KEEPING  THE  BODY  IN  HEALTH 

of  rest  before  it  is  ready  to  undertake  the  digestion  of  another 
meal.  Of  course,  if  food  is  taken  too  frequently,  the  stomach 
A  tired  will  suffer  sooner  or  later,  because  it  will  have  no 
stomach  rest.  You  know  that  the  muscles  of  the  arm  become 
wearied  by  constant  exercise,  and  so  do  the  stomach  muscles, 
which  are  actively  exercised  during  digestion.  "  A  tired  stomach 
is  a  weak  stomach."  When  the  stomach  feels  "tired,"  rest  is 
what  is  needed,  yet  many  people  insist  on  putting  more  food  into 
it,  thus  compelling  it  to  work  when  it  ought  to  be  allowed  to 
rest.  Suppose  this  is  kept  up ;  what  may  happen  to  the  stomach  ? 
Have  you  known  of  such  cases? 

When  food  requiring  several  hours  for  digestion  is  taken  into  the 
stomach  before  the  digestion  of  the  last  meal  is  completed,  the 
stay  of  the  food  in  the  stomach  will  be  so  prolonged  that  the 
stomach  will  have  no  opportunity  for  rest  and  clearance  before 
the  taking  of  the  next  meal.  The  stomach  should  be  empty 
for  a  period  between  meals,  so  that  the  gastric  juice  may  cleanse 
it  and  prepare  it  for  the  next  meal.  It  has  been  shown  that  the 
glands  which  prepare  the  gastric  juice  become  exhausted  by 
work  just  as  do  the  muscles  or  any  other  organ  of  the  body. 
For  this  reason,  they  should  have  a  short  period  of  rest  and 
recuperation  between  meals. 

The  number  of  meals  needed  daily  depends  upon  one's  age  and 
upon  the  nature  and  quantity  of  the  food  taken  at  the  meals, 
A  baby,  who  takes  only  a  small  quantity  of  easily  digested  food 
at  each  meal,  requires  food  at  frequent  intervals.  As  it  grows 
larger  and  its  meals  increase  in  amount,  the  interval  between 
meals  should  be  lengthened.  By  the  time  it  gets  its  teeth  and 
is  able  to  eat  solid  food,  three  meals  a  day  are  quite  sufficient. 
Great  numbers  of  people  in  the  world  eat  only  two  meals  a 
day.  This  is  the  custom  of  the  natives  of  India,  of  South  Amer- 
ica, and  of  many  semicivilized  nations.  Among  savage  tribes^ 


EATING  FOR  HEALTH  AND   PLEASURE  49 

one  meal  a  day  is  the  prevailing  custom.  Though  the  Eskimo 
hunter  sets  out  fasting  in  his  kayak  for  a  long  day's  hunt,  he 
eats  nothing  until  after  he  returns  from  his  perilous  work. 
The  ancient  Greeks,  Hebrews,  and  Persians  ate  but  two  meals 
a  day.  It  is  therefore  evident  that  one  can  be  well  nourished 
on  two  meals  a  day.  In  modern  times  many  persons  have 
adopted  this  custom  with  benefit  to  themselves. 

If  more  than  two  meals  are  needed  by  any  group,  it  is  by  those 
who  are  engaged  in  severe  muscular  labor.  Such  persons  are 
better  able  to  digest  a  third  meal  than  those  whose  work  is 
sedentary,  as  we  say.  If  a  third  meal  is  taken  by  sedentary  work- 
ers, it  should  be  very  light. 

What  has  been  said  about  too  frequent  eating  shows  that  the 
practice  of  eating  sweetmeats,  cookies,  ices,  nuts,  and  such 
things  between  meals  is  a  very  harmful  one.  It  is  a  certain 
cause  of  indigestion,  for  no  stomach  can  long  endure  such  treat- 
ment. By  forming  this  bad  habit  in  childhood,  many  persons 
lay  the  foundation  for  much  suffering  from  dyspepsia  later  in 
life. 

Digestion  cannot  be  well  performed  during  sleep,  for  then  the 
stomach  is  very  slow  in  its  work.  Bad  digestion  and  restless 
sleep  are  often  the  result  of  late  eating.  Through  Hindrances 
the  habit  of  eating  just  before  going  to  bed,  many  to 
persons  suffer  from  sleeplessness,  bad  dreams,  and  digesti°n 
similar  troubles,  and  arise  in  the  morning  very  dull,  because 
the  work  of  nutrition  has  been  hindered.  They  usually  go  to 
sleep  quite  readily  but  are  likely  to  awaken  before  the  night's 
rest  is  finished,  and  are  unable  to  go  to  sleep  again.  This  is 
due  mainly  to  discomfort  caused  by  an  excess  of  food  and 
uneliminated  waste  matters. 

Usually  no  food  should  be  taken  within  four  hours  before 
retiring,  except  by  young  children.  This  will  allow  time  for 


50  KEEPING  THE  BODY  IN  HEALTH 

the  stomach  to  finish  its  work  and  pass  the  food  into  the  small 
intestine.  Then  the  work  of  digestion  may  be  completed  with- 
out disturbance.  If  any  food  at  all  is  taken  shortly  before 
retiring,  it  should  be  ripe  fruit,  or  fruit  juice,  which  does  not 
require  digestion,  but  is  ready  for  immediate  use. 

Another  cause  of  indigestion  which  is  closely  related  to  those 
we  have  studied,  is  irregularity  in  the  time  of  meals.  Our  bodies 
try  to  form  regular  habits.  This  is  especially  true  with  respect 
to  digestion.  If  a  meal  is  taken  at  a  regular  hour,  the  stomach 
will  become  accustomed  to  receiving  food  at  that  hour  and  will 
be  prepared  for  it.  If  meals  are  eaten  irregularly,  the  stomach 
does  not  know  what  to  expect.  The  food  takes  it  by  surprise, 
so  to  speak,  and  it  is  never  in  a  proper  state  of  readiness  for  the 
prompt  and  perfect  performance  of  its  work.  You  must  remem- 
ber that  the  action  of  the  digestive  organs,  like  that  of  all  the 
other  organs,  is  rhythmical,  —  that  is,  it  takes  place  at  regular 
intervals  or  periods.  It  is  far  better,  however,  to  omit  a  meal 
than  to  eat  when  not  hungry,  or  to  introduce  into  the  stomach  a 
new  supply  of  food  when  it  already  contains  some  in  the  process 
of  digestion,  or  before  it  has  been  given  an  opportunity  to  rest. 

Instead  of  omitting  a  meal  when  it  is  not  convenient  to  take 
it  at  the  regular  time,  it  is  well  to  eat  a  little  fruit,  so  as  to  keep 
up  the  normal  intestinal  activity,  which  is  necessary  for  the 
proper  emptying  of  the  colon.  Fruit  does  not  require  much  work 
of  the  stomach  and  is  refreshing  and  acceptable  even  when  one 
does  not  have  an  appetite  for  other  foods. 

Violent  exercise,  either  just  before  or  just  after  eating,  is  a 
hindrance  to  digestion.  It  takes  the  blood  away  from  the 
stomach  to  other  parts  of  the  body,  so  that  the  stomach  is  de- 
prived of  the  energy  needed  for  good  digestion. 

For  the  same  reason  it  is  not  well  to  eat  when  one  is  very 
tired.  The  energy  needed  for  the  work  of  digestion  is  lacking 


EATING  FOR  HEALTH  AND  PLEASURE  51 

in  a  person  who  is  in  an  exhausted  condition,  and  the  food 
is  likely  to  remain  in  the  stomach  for  some  time  undigested. 
If  food  is  needed  by  one  who  is  very  tired,  only  a  small  quantity 
of  an  easily  digested  kind  should  be  taken.  Nitrogenous  foods, 
such  as  meat  and  eggs,  are  especially  harmful  to  a  person  who  is 
very  tired.  Thin,  well-boiled  gruel,  a  cup  of  vegetable  broth, 
or  better  still,  a  glass  of  fruit  juice,  are  the  best  foods  for  tired 
people. 

One  should  not  eat  when  he  is  tired ;  neither  should  one  eat 
when  excited  or   angry   or    irritated    in    any  way.     Professor 
Pavlov  found  that  no  gastric  juice  was  formed  in 
the  stomach  of  a  dog  if  the  animal  was  annoyed  or  digestion 
irritated  while    eating.     Experiments  made  by  Dr.  is  influ- 
Cannon  of  Harvard  University  show  that  digestion  enced  by 
in  the  small  intestine,  as  well  as  in  the  stomach,  is 
greatly  influenced  by  the  mental  state.     He  placed  a  cat  under 
the  X-ray,  so  that  he  could  see  the  stomach  and  the  intestine. 
The  cat  was  given  some  bread  and  milk  containing  bismuth, 
which  made  the  food  visible  under  the  X-ray.     The  digestive 
juices   began  to  flow,  the  stomach  and  intestines  began  their 
muscular  work,  digestion  was  going  on  properly,  and  the  cat 
was  purring  in  comfort  after  her  good  meal,  until  something 
was  done  to  make  her  nervous ;  then  purring  ceased,  and  all 
the  digestive  work  began  to  slow  up.     As  the  cai  became  very 
much  excited  and  angry  and  began  to  spit,  the  digestive  juices 
ceased  to  flow,  the  muscles  stopped  work,   and   the  digestive 
process  came  to  a  standstill.     The  work  of  digestion  stopped 
entirely  until  pussy  was  petted  into  a  good  humor. 

The  mind  should  be  in  a  cheerful  frame  while  food  is  being 
eaten  and  digested.  What  sort  of  conversation  should  there 
be  at  the  table?  Arguments  or  disagreements  and  everything 
of  an  unpleasant  nature  should  be  carefully  avoided.  The 


KEEPING  THE  BODY  IN  HEALTH 


ancient  custom  of  having  a  jester  at  the  table  to  make  people 
laugh  while  eating  was  good  for  their  health  as  well  as  for  their 
humor.  " Laugh  and  grow  fat"  is  an  old  maxim. 

A  natural  and  healthy  appetite  is  the  best  guide  as  to  how 
much  we  should  eat.  If  one  eats  in  a  proper  manner,  chewing 
The  every  morsel  until  it  is  liquid,  his  appetite  will  guide 

normal  him  in  the  selection  of  the  food  needed  and  will  make 
guide  known  to  him  when  he  has  had  enough  of  protein, 

starch,  fat,  or  acid.  You  already  know  something  about  the 
remarkable  signaling  system  by  means  of  which  the  digestive 


HERE  ARE  SOME  OF  PROFESSOR  PAVLOV'S*  .DOGS. 

work  is  controlled.  The  regulation  of  the  appetite  is  an  in- 
teresting part  of  this  system.  There  are  certain  centers  in  the 
brain  which  have  been  called  "hunger  centers."  When  the  body 
is  in  need  of  food,  a  message  is  sent  up  to  these  hunger  centers 
and  from  them  a  sensation  is  transmitted  to  the  mouth  by  the 
nerves  of  taste,  creating  the  desire  for  food  that  we  call "  appetite." 
When  enough  of  a  certain  kind  of  food  has  been  received  into 
the  body,  the  " hunger  centers"  are  notified  that  no  more  is 


54  KEEPING  THE  BODY  IN  HEALTH 

needed,  and  the  appetite  for  that  particular  food  is  cut  off. 
Dr.  Pavlov's  dogs  continued  eating  with  unabated  appetite  for 
hours  at  a  time  when  their  food  passed  into  a  dish  instead  of 
into  the  stomach.  Since  no  food  was  received  into  the  body, 
no  message  was  sent  up  to  the  brain  to  cut  off  the  supply. 

When  one  bolts  his  food,  he  cannot  discover  when  he  has  had 
enough,  for  some  of  the  food  must  get  into  the  blood  before  the 
"hunger  center"  will  ring  the  bell,  so  to  speak,  for  the  supply  to 
cease.  When  one  hurries  food  into  the  stomach,  he  gets  more 
than  he  needs  before  the  "hunger  center"  finds  it  out,  and  he 
stops  only  when  he  is  so  full  that  he  cannot  eat  any  more. 

We  can  now  see  how  some  of  the  bad  habits  that  we  have  been 
considering  —  eating  too  fast,  drinking  too  much  at  meals,  and 
Waste  in  taking  too  great  a  variety  of  food  at  a  meal  —  lead 
eating  to  another  bad  habit,  —  that  of  eating  too  much. 

The  digestive  organs  are  then  overtaxed  to  take  care  of  a  quantity 
of  food  that  is  not  needed.  All  food  taken  into  the  body  beyond 
what  is  needed  is  not  only  of  no  use  but  is  actually  harmful. 
If,  in  repairing  a  house,  a  great  deal  of  unnecessary  material  were 
carried  into  the  house,  the  surplus  amount  would  only  be  in  the 
way  of  the  workmen,  and  they  would  have  to  spend  their  strength 
in  carrying  it  out.  It  is  just  so  with  the  little  cell  workers  of 
the  body. 

HEALTH  PROBLEMS 

1.  Take  a  slice  of  bread  and  chew  it  until  it  "swallows  itself."    How 
does  it  taste  ?     Explain. 

2.  Put  your  hand  into  a  bowl  of  ice  water;   how  long  can  you  endure 
it?    How  long  could  you  keep  your  face  in  it?     How  do  you  think  your 
stomach  would  like  to  have  a  bowl  of  ice  water  poured  into  it  ? 

3.  Do  you  know  any  person  who  has  fallen  into  the  habit  of  nibbling 
at  food  between  meals?    Describe  such  a  person's  health  and  disposition. 

4.  Look  up  the  meaning  of  the  word  dyspepsia.     Then  make  out  a  list 
of  the  eating  habits  one  should  form  in  order  to  avoid  this  disease. 


EATING  FOR  HEALTH  AND   PLEASURE  55 

5.  How  would  it  do  for  one  to  acquire  the  habit  of  eating  breakfast  one 
day  at  8  o'clock,  the  next  day  at  10  o'clock,  the  following  day  at  9  o'clock, 
and  the  day  after  at  another  hour?     Would  it  make  any  difference  if  this 
irregularity  occurred  at  dinner  or  at  supper  ? 

6.  How  would  it  do  to  jump  up  from  the  dinner  table  and  immediately 
run  a  long  race  with  a  companion?     Explain. 

REVIEW  QUESTIONS 

1.  What  has  Nature  especially  provided  to  induce  people  to  chew  food 
thoroughly  ? 

2.  Should  food  be  attractive  to  the  eye  as  well  as  to  the  smell  and  taste? 
Why? 

3.  How  long  should  food  be  kept  in  the  mouth? 

4.  What  may  happen  in  the  stomach  if  food  is  not  thoroughly  chewed 
before  it  is  swallowed? 

5.  Why  do  people  so  often  bolt  their  food? 

6.  What  is  the  danger  in  eating  moist  foods  like  mushes  and  soups? 
When  one  eats  such  foods,  what  special  care  must  be  taken  ? 

7.  How  do  farmers  sometimes  prevent  horses  from  bolting  their  food? 

8.  What  bad  habit  often  causes  one  to  drink  large  quantities  of  liquids 
at  meals?     What  is  the  harm  in  so  doing? 

9.  What  temperature  is  required  for  digestion?     How  will  a  glass  of 
ice  water  affect  this  temperature? 

10.  What  is  the  harm  in  taking  very  hot  drinks  during  meals? 

11.  If  one  must  drink  during  meals,  how  should  one  do  it? 

12.  Is  a  variety  of  food  at  a  meal  good  for  the  health?     Why? 

13.  Why  is  it  harmful  to  eat  a  meal  before  the  previous  meal  has  been 
digested? 

14.  How  should  the  number  of  meals  a  day  be  varied  according  to  one's 
age? 

15.  Is  there  any  harm  in  eating  just  before  going  to  bed?     If  food  must 
be  taken  just  before  bedtime,  of  what  kind  should  it  be? 

1 6.  Is  there  any  harm  in  eating  at  irregular  times?     Why? 

17.  Is  there  any  harm  in  taking  violent  exercise  before  a  meal?    Why? 
What  of  eating  when  one  is  tired  ? 

18.  How  does  the  state  of  one's  mind  influence  digestion? 

19.  What  are  the  "  hunger  centers  "? 


CHAPTER   V 

GETTING  PURE  FOOD  AND  KEEPING  IT  PURE 

IN  early  pioneer  days,  when  our  country  was  young,  there 
were  no  cities  and  no  factories.  People  lived  far  apart,  and  each 
family  had  to  depend  for  its  food  chiefly  upon  its  own  private 
supplies.  The  people  raised  their  own  grain  and  had  it  ground 
into  flour.  They  made  sugar  from  the  sap  of  maple  trees.  Their 
chickens  supplied  them  with  eggs,  and  their  cows  with  milk. 
Each  household  prepared  foods  for  winter  use  by  drying,  salting, 
and  other  means. 

But  as  the  country  has  become  thickly  populated,  most  of 
the  people  have  gathered  together  in  large  cities,  where  it  is  not 
possible  for  them  to  produce  their  own  foods.  So  they  have  to 
depend  upon  public  supplies  for  food.  The  "milk  train"  comes 
in  from  the  country  early  every  morning,  bringing  from  the  farms 
the  milk  supply  for  a  whole  city.  Our  flour  comes  to  us  in 
barrels  or  bags  from  distant  mills  in  the  grain-growing  sections 
of  the  country.  We  must  purchase  our  meats  from  a  public 
shop  or  market.  Our  eggs,  butter,  canned  and  dried  fruits,  and 
all  such  articles  come  from  public  stores  which  supply  many 
families.  Of  course,  if  you  live  in  the  country,  you  may  pro- 
duce your  own  vegetables,  eggs,  milk,  and  butter;  but  you 
probably  buy  your  flour,  sugar,  fruit,  and  other  foods  from  public 
supplies. 

So  long  as  each  family  provided  its  own  food,  it  was  easy  to 
tell  whether  the  food  was  clean  and  of  good  quality.  You  may 
know,  for  instance,  that  the  milk  from  your  own  cow  is  rich, 

56 


GETTING  PURE  FOOD  AND  KEEPING  IT  PURE 


57 


DO  YOU  THINK  BREAD  BAKED  IN  A  PLACE  LIKE  THIS  WILL  BE  CLEAN  AND  WHOLE- 
SOME ?  HAVE  YOU  VISITED  THE  BAKERIES  IN  YOUR  COMMUNITY  TO  SEE  WHETHER  THEY 
ARE  LIGHT  AND  CLEAN? 

fresh,  and  pure.     But  the  milk  you  buy  from  a  city  store  may 
have  had  part  of  the  cream  removed ;  it  may  have  had  water, 
coloring  matter,  or  some  harmful  substance  added  to  The 
it ;  it  may  be  swarming  with  harmful  bacteria.     The  adultera- 
bread  made  at  home  from  wheat  grown  in  your  own  tion  of 
fields  and  ground  in  a  hand  mill,  you  know  to  be 
wholesome ;  but  the  bread  you  buy  at  the  store  may  have  been 
made  from  flour  from  which  the  most  nutritious  portion  was  re- 
moved in  the  process  of  milling,  and  it  may  have  had  alum 


58  KEEPING  THE  BODY  IN  HEALTH 

added  to  increase  the  whiteness.  It  may  have  been  baked  in  an 
unsanitary  bakery.  In  some  cities,  bakeries  are  carefully  in- 
spected. Do  you  know  if  this  is  true  of  the  bakery  where  your 
bread  is  made  ?  You  probably  know  the  age  of  the  eggs  laid 
by  your  own  hens;  but  the  " fresh"  eggs  you  buy  at  the  store 


PARTICULAR  CARE  SHOULD  BE  TAKEN  TO  KEEP  FLOUR  FREE  FROM  DIRT  AND  ALL  ADULTERA- 
TION,  SINCE   BREAD  IS  THE   PRINCIPAL  ARTICLE  OF  FOOD. 

may  have  been  laid  months  before  and  packed  and  kept  in  cold 
storage. 

You  see,  then,  that  in  getting  food  from  public  supplies  you 
run  some  risk.  The  articles  may  not  be  what  they  appear  to 
be.  Sometimes  a  cheap  substitute  is  used  instead  of  the  real 
foodstuff.  The  material  used  may  or  may  not  be  harmful; 
but  the  food  is  a  counterfeit.  This  is  called  adulteration  of  food. 

In  all  countries  and  in  all  ages  it  seems  to  have  been  the  prac- 
tice of  dishonest  dealers  to  adulterate  food  in  order  to  make  more 


GETTING  PURE  FOOD  AND  KEEPING  IT  PURE    59 

money  through  its  sale.  When  Plato,  one  of  the  ancient  Greeks, 
was  planning  a  model  city,  he  declared  that  there  should  be  "no 
adulteration  of  food  and  no  tricks  of  trade." 

It  is  only  within  quite  recent  years  that  people  in  this  country 
have  begun  to  find  out  the  extent  to  which  adulteration  of  foods 
is  practiced  and  the  lack  of  care  shown  by  dealers  in  regard  to 
the  purity  of  foods  sold.  Those  who  look  after  the  health  of 
the  people  in  our  country  to-day  are  trying  to  get  a  pure  food 
supply  for  the  poor  and  the  rich  alike.  In  most  cities  now  there 
are  food  inspectors  who  try  to  prevent  the  adulteration  of 
foods.  There  is  a  force  of  at  least  one  hundred  of  these  food 
inspectors  in  New  York  City  alone.  Every  store  in  the  city 
is  visited  twice  a  month  in  winter  and  three  times  in  summer. 
The  great  wholesale  houses  are  inspected  daily,  and  a  close 
watch  is  kept  upon  the  meat  markets  and  slaughterhouses. 
One  result  of  this  inspection  is  that  unfit  foods  are  sorted  out 
and  destroyed,  and  large  quantities  are  being  constantly  seized. 

A  very  dangerous  method  of  adulteration  is  the  use  of  chemi- 
cals to  preserve  and  color  foods.     Dyes  tuffs  made  from  coal  tar 
are  used  to  color  counterfeit  materials.     In  a  little 
booklet  sent  out  by  the  United  States  Department  coioring 
of  Agriculture  to  various  schools  and  colleges,  there  matter 
are   samples   of   cloths  presented   which   have   been  used  in 
colored  with  the  dyes  secured  from  such  counterfeit 
foods.     One  sample  is  a  brilliant  cardinal,  the  dye  for  which  had 
been  obtained  from   "blood  peaches."     Another  sample  is  a 
bright  orange,  the  color  of  which  had  come  from  bottled  "orange 
juice."     Still  other  samples  are  green  and  purple,  the  color  for 
which  had  been  derived  from  preserved  cherries  and  plums. 

Cheap  candies  very  commonly  contain  harmful  coloring  mat- 
ter and  other  adulterants.  Sweetened  tallow  and  grease  form 
the  rilling  of  certain  chocolate  creams.  Until  a  few  years  ago, 


60  KEEPING  THE  BODY  IN  HEALTH 

many  candy  manufacturers  used  shellac  for  coating  chocolates. 
Then  the  government  forbade  its  use.  The  honest  manufac- 
turers stopped  using  it,  but  the  dishonest  ones  kept  on.  At 
a  recent  New  York  Pure  Food  Show,  one  of  the  exhibits 
consisted  of  three  bottles.  In  Bottle  No.  i  there  were  what 
seemed  to  be  candy-covered  peanuts.  In  Bottle  No.  2  there 
were  the  same  kind  of  peanuts  after  the  coating  had  been  taken 
off ;  and  in  Bottle  No.  3  was  the  coating  that  had  been  washed 
off — four  ounces  of  furniture  shellac  or  floor  polish.  Many 
glossy  candies  get  their  polish  just  as  woodwork  does,  —  by  a 
coat  of  varnish.  There  was  also  at  the  Food  Show  a  jar  of 
candies  that  had  been  colored  brown  with  sweetened  house 
paint.  One  of  the  exhibits  was  a  doll  in  gaudy  clothes  which 
had  been  colored  with  coal-tar  dyes  obtained  from  candy  and 
ice  cream.  How  should  you  enjoy  eating  your  chocolate  candies, 
if  you  knew  you  were  swallowing  floor  polish  or  house  paint? 

A  food  inspector,  who  secured  employment  in  a  candy  factory 
in  order  to  find  out  for  himself  all  about  the  conditions  there, 
said:  "I  have  seen  candy  samples  brought  to  the  laboratories 
and  boiled  down ;  then  rags  were  dipped  in  the  stuff ;  and,  after 
the  rags  were  dried,  no  amount  of  washing  would  serve  to  remove 
the  dye.  Imagine  putting  such  material  into  your  stomach 
and  then  wondering  why  you  are  ill!" 

You  can  try  the  following  experiment  for  yourself  sometime 
if  you  think  there  is  any  artificial  coloring  matter  in  fruit  juice, 
jelly,  tomato  catsup,  or  confectioneries.  Boil  some  of  the  sub- 
stance ;  and,  while  it  is  boiling,  put  in  a  small  piece  of  nun's 
veiling  or  a  good  grade  of  white  woolen  dress  goods.  If  the 
substance  dyes  the  cloth,  so  that  the  cloth  after  having  been 
washed  in  cold  water  still  has  a  bright  color,  this  is  evidence 
of  the  presence  of  some  form  of  coal-tar  dye.  A  single  glass  of 
raspberry  soda  water  such  as  is  found  at  soda  fountains  was 


GETTING  PURE  FOOD  AND  KEEPING  IT  PURE    6l 

recently  found  to  contain  sufficient  coal-tar  dye  to  color  two  yards 
of  woolen  cloth.  Would  it  be  good  for  one's  health  to  drink 
this  soda  water  ? 

For  a  long  time,  certain  firms  that  made  a  business  of  pre- 
paring foods  for  sale  added  such  chemicals  as  boracic  acid,  ben- 
zoate  of  soda,  formalin,  salicylic  acid,  and  sulphites  to  jjannfui 
make  the  foods  "keep"  better.     These  preservatives,  preserva- 
as  they  are  called,  do  prevent  foods  from  spoiling.  tives  used 
Through  their  use,  dishonest  men  are  able  to  take  L 
garbage  gathered  from  canning  factories,  —  tomato  skins,  apple 
parings  and  cores,  worm-eaten  and  decayed  parts  cut  from  fruit, 
and,  after  treating  them  with  preservatives  and  with  colorings, 
to  sell  them  as  tomato  catsup,  apple  butter,  soup,  jam,  or  mince- 
meat. 

Sulphite  of  soda  and  other  chemicals  are  very  frequently  used 
in  making  sausage  and  Hamburger  steak.  This  is  because  these 
preparations  are  sometimes  made  of  odds  and  ends  of  meat  which 
cannot  be  used  in  any  other  way.  The  butcher  often  keeps  under 
his  counter  a  large  tin  can  into  which  he  throws  the  trimmings  and 
odds  and  ends  of  meats  which  are  not  salable.  These  are  some- 
times left  to  accumulate  until  the  can  is  full.  In  the  meantime 
mold  and  germs  grow  in  and  upon  the  meat,  flies  visit  the  can 
and  deposit  their  eggs  which  often  hatch  out  into  maggots,  and 
so  it  is  no  wonder  that  sausage  meat  and  Hamburger  steak,  when 
made  by  a  dishonest  butcher  from  such  refuse,  contain  enormous 
quantities  of  germs.  Do  you  know  that  decaying  meats  treated 
with  preservatives  and  then  canned  and  shipped  to  our  soldiers 
during  the  Spanish-American  war  were  the  cause  of  a  terrible 
outbreak  of  sickness  and  the  loss  of  many  lives? 

Even  good  foods  chemically  treated  are  likely  not  to  be  of 
much  use  to  the  body.  The  United  States  Bureau  of  Chemistry, 
when  Dr.  Harvey  Wiley  was  at  its  head,  undertook  to  test  the 


62  KEEPING  THE  BODY  IN  HEALTH 

matter.  A  number  of  young  men  who  were  willing  to  make  the 
test  put  themselves  under  certain  rules  of  living.  These  young 
men,  known  as  Dr.  Wiley's  "poison  squad,"  were  fed  for  weeks 
on  foods  containing  preservatives,  and  the  effects  were  carefully 
watched.  After  long  and  painstaking  trials,  it  was  concluded 
that  all  chemical  preservatives  are  more  or  less  harmful  when 
used  in  foods.  Should  you  expect  anything  different? 

On  June  30,  1906,  the  United  States  government  passed  what 
is  known  as  the  Pure  Food  Law.  This  does  not  forbid  the  use 
of  preservatives  and  coloring  matter  in  foods,  but  it  requires 
that  when  they  are  used  it  shall  be  so  stated  on  the  label.  This 
is  a  protection  to  those  who  do  not  want  to  use  foods  with  chemi- 
cals in  them.  Do  you  not  prefer  foods  that  have  not  been 
treated  with  such  chemicals  ? 

When  the  housekeeper  preserves  her  own  fruits  and  vege- 
tables, she  is  careful  to  use  only  perfectly  sound,  fresh  products, 
in  which  decay  has  not  started.  The  only  preservative  that  she 
uses  is  heat.  By  means  of  heat  she  destroys  all  the  germs  which 
cause  decay,  and  then  she  carefully  seals  up  her  jars  so  that  no 
more  germs  can  enter. 

Certain  food  manufacturers  undertook  some  experiments  to 
find  out  if  it  was  necessary  to  use  preservatives  in  food  canned 
for  public  supplies.  They  proved  that,  when  sound  products 
are  used,  no  preservatives  are  needed.  The  use  of  any  pre- 
servative in  food  is  therefore  likely  to  mean  one  of  two  things : 
either  that  the  food  products  were  not  of  the  best  quality,  or 
that  they  were  not  canned  in  a  careful,  clean,  and  sanitary 
manner. 

There  are  other  ways  besides  adulteration  by  which  food  may 
be  made  unsafe.  Quite  often  the  bacteria  which  are  the  cause 
of  disease  get  into  food  through  lack  of  care  in  handling  it  or 
storing  it.  Sometimes,  too,  foods  contain  the  poisons  which 


GETTING  PURE  FOOD  AND  KEEPING  IT  PURE    63 

result  from  decay.     Meat,  eggs,  and  milk  are  foods  especially 
liable  to  contain  these  impurities.     All  animal  foods  decay,  or, 
as  we  say,  " spoil"  very  rapidly.     When  this  process 
has  begun  in  such  foods,  some  very  dangerous  poisons,  handling 
called  ptomaines   and   toxins,    are   formed  in   them,  often 
Certain  savage  tribes  poison  their  arrows  by  striking  ^nakes  food 
the  points  into  the  decayed  flesh  of  dead  animals. 

Canned  meats  are  the  most  common  source  of  meat  poisoning. 
When  the  meat  is  not  properly  cooked  before  it  is  canned,  pto- 
maine poisons  are  likely  to  form  in  the  can.  These  poisons 
are  very  deadly.  They  are  much  like  the  venom  of  snakes,  and 
it  does  not  lessen  the  danger  to  cook  such  food  after  the  poison 
has  formed. 

Sausage  poisoning  or  botulism  sometimes  occurs  from  the  use 
of  tainted  sausage.  Cases  of  botulism  have  recently  been  ob- 
served from  the  use  of  spinach,  beans,  ripe  olives,  and  other  vege- 
tables. The  cause  is  insufficient  heating  in  canning.  No  cases 
of  poisoning  have  occurred  from  the  use  of  olives  canned  in  small 
tin  cans.  When  ripe  olives  are  canned  in  glass  jars  they  may 
not  be  properly  heated.  When  beans  are  "cold  packed,"  they 
may  be  imperfectly  sterilized.  The  germ  which  causes  botulism 
is  destroyed  by  cooking  for  half  an  hour  at  a  boiling  tempera- 
ture. For  safety,  canned  vegetables  should  be  thoroughly 
cooked  before  serving. 

All  canned  foods  when  opened  spoil  more  quickly  than  freshly 
cooked  foods.  Why?  Canned  foods  need  also  to  be  removed 
from  metal  cans  at  once  after  opening.  Why? 

Wholesome  eggs  must  be  fresh.  Of  course,  those  laid  by 
hens  which  have  been  fed  on  clean  foods  are  safest.  It  is  not 
uncommon  for  eggs  that  have  been  packed  and  kept  for  months 
to  be  sold  for  fresh  eggs.  If  there  is  any  doubt  about  the  matter, 
one  can  make  a  test  by  holding  a  suspected  egg  between  the  eye- 


64  KEEPING  THE  BODY  IN  HEALTH 

and  a  lighted  candle  in  a  dark  room.  If  it  is  a  new-laid  egg, 
an  air  space  can  be  plainly  seen  between  the  shell  and  the  lining 
at  the  larger  end.  This  will  be  very  small  in  a  fresh  egg.  A 
large  air  space  shows  that  the  egg  is  old.  If  the  egg  is  really 
bad,  a  number  of  dark  spots  will  be  seen. 

According  to  government  experts,  eggs  are  quite  likely  to 
contain  germs,  even  when  they  are  freshly  laid.  Germs  are 

found  on  an  aver- 
age in  about  one 
egg  in  seven,  con- 
sequently freshly 
laid  eggs  may 
contain  harmful 
germs,  and  should 
be  carefully  in- 
spected before 
cooking  or  eating. 
Many  foods  are 
made  unsafe  be- 
cause of  careless- 

BOY   IS  TESTING   AN  EGG  FOR  FRESHNESS.  .  •,  JV 

ness  in  handling 
them,  and  also  because  of  dust  and  unclean  methods  in  stores. 
For  instance,  bread  may  pass  through  a  half  dozen  pairs  of 
hands,  from  the  time  it  leaves  the  oven  until  it  is  delivered 
at  your  door.  Unless  wrapped  up  it  may  gather  a  lot  of  germs 
on  the  way.  It  is  not  wise  for  one  to  buy  food  that  has  been 
exposed  for  sale  uncovered,  whether  outside  or  inside  a  store. 
Why? 

A  culture  plate  exposed  under  the  glass  show  case  in  a  clean 
bakery  collected  only  fifteen  bacteria  in  ten  minutes,  while  a 
plate  exposed  on  the  open  counter  collected  800  bacteria  in  the 
same  length  of  time.  Fifty  times  as  many  germs  fell  on  the 


GETTING  PURE  FOOD  AND  KEEPING  IT  PURE    65 


THERE  SHOULD  BE  A  "WHITE  LIST"  OF  STORES  IN  EVERY  COMMUNITY  AND  SUPPLIES 
SHOULD  BE  PURCHASED  ONLY  FROM  STORES  ON  THE  LIST.  Do  YOU  NOT  THINK  THAT 
ALL  STORES  WOULD  TRY  TO  KEEP  CLEAN  IF  EVERY  TOWN  HAD  A  "WHITE  LlST?" 

exposed  plate   as  on  the  one  protected    by    the    glass    show 
case.     On  the    same  day,  plates  were  exposed  on  a  sidewalk 
fruit  stand,  and  in  ten  minutes  10,000  bacteria  were  ^    .      „ 
collected,  while  a  plate  exposed  under  a  glass  cover  ness 
collected  only  forty-one  bacteria  in  the  same  length  means 
of  time.     80  the  food  exposed  to  the  dust  of  the  danger 
street  contained  250  times  as  many  germs  as  that  protected 
by  a  coyer-    ?Pr  similar  reasons,  in  sweeping  a  dining  room,  all 


66  KEEPING  THE  BODY  IN  HEALTH 

the  dishes  and  food  should  be  carefully  protected.  If  this  is 
not  done  the  dust  containing  germs  may  easily  become  mixed 
with  the  food  and  do  more  or  less  harm. 

A  group  of  women  in  a  city  that  I  know  devised  the  following 
plan  to  get  clean,  safe  foods.  They  examined  every  store  where 
foods  were  sold  and  made  what  they  called  a ' l  White  List. ' '  Every 
salesman  who  was  found  to  keep  his  store  clean  and  sanitary 
was  given  a  big  placard  bearing  the  words  " White  List"  to  put 
in  his  window.  This  showed  to  everybody  that  the  foods  of 
that  store  might  be  eaten  without  danger  to  anyone's  life.  The 
women  agreed  to  buy  their  foods  only  at  stores  enrolled  on  the 
"White  List."  You  can  imagine  what  a  cleaning  up  time  there 
was.  Clean  hands,  clean  aprons,  well-protected  food,  and  a 
city  full  of  neat  and  well-kept  markets  resulted  from  this  cam- 
paign. 

Intense  cold  checks  the  growth  of  bacteria,  while  intense  heat 
kills  bacteria.  Drying  also  removes  the  moisture  necessary  for 
germ  life.  All  these  methods  are  used  to  preserve  food.  Storage 
in  some  cold  place  is  the  most  common  method  of  keeping  fresh 
foods  like  fruits,  vegetables,  meats,  milk,  and  eggs.  Some  of 
the  methods  for  keeping  the  food  cool  are  by  suspension  of  the 
food  in  deep  wells,  storage  in  cool  cellars,  covering  with  ice 
water,  the  use  of  porous  containers  hung  in  a  current  of  air,  the 
placing  of  the  food  in  closed  vessels  which  are  then  covered  with 
wet  leaves  or  buried  in  wet  sand.  Why  should  each  of  these 
methods  be  useful? 

The  best  device  for  preserving  foods  by  cold  is  an  ice  box  or 
refrigerator,  such  as  you  have  all  seen.  But  in  the  use  of  the 
refrigerator  there  is  need  for  great  care  and  cleanliness.  My 
little  friend  Jane  has  the  care  of  the  refrigerator  for  her  share 
of  the  home  work.  She  keeps  strict  watch  of  the  iceman  to 
make  sure  that  he  washes  the  ice  before  he  puts  it  into  the  box. 


GREAT  CARE  SHOULD  ALWAYS  BE  TAKEN  TO  KEEP  THE  ICE  BOX  CLEAN,  SWEET,  AND  WHOLE- 
SOME.     THE   ICE   SHOULD  ALWAYS   BE   WASHED   BEFORE   IT  IS  PUT  INTO  THE   BOX. 


IF  THE   ICE   BOX   IS    NOT    THOROUGHLY    CLEANSED   AT   LEAST  ONCE    A    WEEK,    IT   WILL  BE 
DIFFICULT   TO    KEEP   THE    FOOD    MOIST  AND   WHOLESOME. 


68  KEEPING  THE  BODY  IN  HEALTH 

She  knows  that  if  it  is  lake  or  river  ice  it  may  have  in  it  fragments 
of  grass  or  leaves  which,  as  the  ice  melts,  may  cling  to  the  box 
or  water  pipes.  So  once  each  week  she  takes  out  all  the  ice, 
wrapping  it  in  newspapers  to  prevent  waste.  Then  she  removes 
all  the  food  from  the  ice  box  and  covers  this  from  dust.  Next 
she  scrubs  out  the  ice  compartments  and  cleans  the  drip  pipe 
through  which  the  water  flows  away.  This  she  scalds  with  a 
strong  solution  of  boiling  sal  soda  water.  She  takes  out  the 
shelves  and  scrubs  them  well  in  a  pan  of  hot  soapsuds.  After 
rinsing  them  she  dries  them. 

She  gives  careful  attention  to  all  parts  of  the  food  chamber. 
She  even  scrubs  the  water  pan.  When  every  part  is  clean  and  dry, 
H  ..  the  ice  is  put  back,  the  shelves  are  replaced  and  the 
cleans  the  doors  closed.  As  soon  as  the  temperature  within  is 
refriger-  cooled  to  50  degrees,  the  food,  too,  is  put  back.  Do 
you  wonder  how  Jane  knows  when  the  box  is  cold 
enough?  She  keeps  a  thermometer  inside  the  refrigerator  all 
the  tune,  for  she  has  found  that  the  foods  spoil  in  a  refrigerator 
which  has  become  warm,  even  more  quickly  than  when  they 
are  kept  outside  in  warm  air.  A  thermometer  is  the  best  means 
of  testing  the  temperature  within  the  refrigerator.  Jane  tries 
always  to  keep  it  at  about  45  or  50  degrees.  Occasionally  the  ice 
gets  very  low.  Then  she  takes  the  food  out  until  the  iceman 
brings  a  new  supply  of  ice,  and  the  air  in  the  food  chamber 
becomes  cold  again.  Meanwhile,  the  foods  are  kept  cool  in 
some  of  the  other  ways  of  which  mention  has  been  made.  The 
next  time  she  gets  more  ice,  or  takes  better  care  of  the  ice  so 
that  it  will  not  melt  so  fast. 

Before  storing  foods  in  the  ice  box,  Jane  always  puts  them  in 
clean  dishes.  Anything  spilled  in  the  food  chamber  is  wiped  up 
at  once.  Foods  are  not  put  in  while  they  are  hot  or  while  giving 
off  steam.  Of  course,  the  food  chamber  needs  more  frequent 


GETTING  PURE   FOOD  AND   KEEPING  IT  PURE         69 

cleaning  than  the  ice  compartment.  Every  day  Jane  wipes  the 
shelves ;  and  once  each  week,  or  oftener  in  warm  weather,  she 
gives  the  food  chamber  a  thorough  cleansing. 

HEALTH  PROBLEMS 

1.  Ask  your  father  and  mother  whether  they  buy  more  of  their  food 
from  public  supplies  than  their  parents  did.     If  there   is  a  difference, 
what  has  caused  it  ? 

2.  Are  there  food  inspectors  in  the  community  in  which  you  live?     If 
so,  how  many  of  them  are  there?    Just  what  do  they  do?    Have  you 
known  of  their  destroying  any  foodstuffs  ? 

3.  Can  you  tell  by  the  naked  eye  when   the  foods  bought  at  stores 
are  adulterated  ?     Take   canned   fruits,  for   instance ;    how  can  you   tell 
when  they  are  adulterated  as  to  color  or  flavor  or  quality? 

4.  Can  you  tell  when  candies  are  adulterated?    How?     Make  a  test 
of  some  cheap  candy  bought  at  a  store,  and  give    the  results  to   the 
class. 

5.  If  you  can,  get  some  small  samples  of  boracic  acid,  benzoate  of  soda, 
formalin,  salicylic  acid,  and  sulphite  of  soda  to  show  the  class.     Why  do 
they  preserve  food  ? 

6.  Do  you  know  whether  chemical  preservatives  are  ever  used  in  your 
family  in  canning  fruits  or  vegetables?     Ask  your  mother  whether  she 
thinks  she  can  put  up  goods  that  will  keep  without  using  any  of  the  chemi- 
cals mentioned  above. 

7.  Have  you  ever  heard  of  any  one's  being  poisoned  by  eating  canned 
meat  or   fish?      Do    you    know  whether   oysters    are    likely  to    contain 
ptomaines  ? 

8.  Visit  a  bakery  in  your  town  or  city,  and  tell  the  class  what  you  think 
about  the  methods  used  to  keep  the  food  clean  and  pure.     Are  the  persons 
clean  who  do  the  baking  ? 

9.  Visit  a  meat  shop  in  your  town  or  city,  and  tell  the  class  whether 
the  butcher  takes  pains  to  keep  his  meats  pure  and  clean. 

10.  Is  there  a  "  White  List "  of  stores  in  your  city?    If  not,  would  it  be 
well  to  have  one  ?    Why  ? 

11.  Look  into  your  ice  box  when  you  go  home,  and  say  whether  you 
think  it  is  a  thoroughly  wholesome  place  in  which  to  store  food. 


70  KEEPING   THE  BODY  IN  HEALTH 

REVIEW  QUESTIONS 

1.  How  did  each  family  get  its  food  in  the  early  pioneer  days? 

2.  Where  do  people  in  the  city  get  their  food  to-day? 

3.  Explain  how  we  secure  the  different  articles  of  food  which  we  use. 

4.  Why  is  it  difficult  for  people  to-day  to  tell  whether  their  food  is  pure  ? 

5.  Why  have  food  inspectors  been  appointed  in  large  cities,  and  what  is 
their  work  ? 

6.  What  does  it  mean  to  adulterate  food?    Why  do  men  adulterate 
food? 

7.  Do  the  inspectors  find  much  food  that  is  not  fit  to  eat?     What  do 
they  do  with  it  ? 

8.  What  is  a  common  method  of  adulterating  canned  meats? 

9.  \Vhat  is  a  common  method  of  adulterating  honey  and  jelly? 
10.   Tell  about  the  adulteration  of  food  with  tar  dyes. 

n.  Describe  especially  the  methods  of  adulterating  candy. 

12.  What  experiment  can  you  make  to  determine  whether  there  is  color- 
ing matter  used  in  fruit  juices,  jelly,  or  confectionery  ? 

13.  Are  coal-tar  dyes  harmful  when  taken  into  the  stomach? 

14.  What  is  the  Pure  Food  Law  ?     Is  it  necessary  to  have  such  laws  in 
this  country? 

15.  When  a  manufacturer  must  use  a  chemical  preservative,  what  is 
probably  true  about  the  quality  of  the  fruit  or  vegetables  he  cans  ? 

1 6.  What  is  the  name  of  the  poison  which  is  sometimes  found  in  canned 
meat,  or  in  fish  or  oysters  ? 

17.  When  poisons  have  been  formed  in  a  can  of  food  can  you  purify 
the  contents  by  boiling  ?     Why  ? 

1 8.  How  soon  after  a  can  is  opened  should  the  contents  be  emptied? 


CHAPTER  VI 

THE  BLOOD 

MORE  than  a  century  ago  a  great  English  scientist,  John 
Hunter,  performed  some  interesting  experiments.  He  cut  the 
nerve  trunk  that  supplied  the  limb  of  an  animal  and  then  watched 
the  results.  The  limb  was  paralyzed,  but  the  flesh  remained 
warm,  the  circulation  continued,  the  hair  and  nails  grew  as  be- 
fore, and  so  the  limb  remained  alive.  The  muscles  shrank  for 
want  of  use,  but  otherwise  no  evidence  of  disease  appeared.  An 
experiment  was  then  made  with  another  limb.  The  arteries 
conveying  the  blood  to  the  part  were  tied,  while  the  nerves  were 
left  undisturbed.  Note  the  different  result.  Within  a  few 
hours  the  limb  became  cold.  It  became  also  livid,  purple,  and 
finally  black.  Soon  the  flesh  began  to  fall  away.  The  limb 
had  died  and  had  become  simply  a  decaying  mass.  The  blood 
These  experiments  clearly  showed  that  it  is  the  blood  renews 
that  maintains  the  life  of  the  tissues  through  which  the  body 
it  flows.  The  blood  constantly  replaces  the  worn-out  cells  and 
fibers,  so  that  by  its  agency  the  body  is  continually  renewed. 

The  eyes  with  which  we  look  out  upon  the  world  to-day  are 
not  composed  of  just  the  same  cells  as  those  which  pictured  for 
our  brain  the  happenings  of  the  outer  world  a  year  or  two  ago. 
The  muscles  which  move  us  about  and  the  brain  and  nerves  with 
which  we  think  and  feel  are  likewise  new.  All  the  soft  parts  of 
the  body  are  so  rapidly  changed  that  the  great  mass  of  the  body 
is  renewed  every  few  months  or,  at  the  longest,  every  few  years. 

71 


72  KEEPING  THE  BODY  IN  HEALTH 

It  is  by  means  of  the  blood  that  this  body  rebuilding  is  con- 
stantly carried  forward. 

The  blood  has  been  called  the  " carrier"  of  the  body.  It  re- 
ceives the  digested  food  from  the  alimentary  canal  and  the  oxy- 
gen from  the  lungs  and  carries  them  to  the  waiting  tissues  in  all 
parts  of  the  body.  The  smallest  cell,  no  matter  how  far  removed 
Irom  the  great  centers  of  life,  receives  its  due  share  of  nutriment 
through  the  medium  of  the  blood.  In  return  for  the  new  ma- 
terial which  it  supplies  to  the  tissues,  the  blood  carries  away  the 
cell  wastes  to  the  organs  by  which  they  are  expelled  from  the 
body.  Is  this  constant  exchange  of  matter  in  the  body  essential 
to  life?  Do  you  think  that  the  more  rapidly  old  material  is 
carried  away  and  new  material  deposited  in  its  place,  the  more 
rapidly  the  wheels  of  life  will  turn  and  the  more  one  will  really 
live? 

As  you  look  at  blood  it  appears  to  be  red,  but  when  you  ex- 
amine it  under  the  microscope,  it  no  longer  looks  red.  It  is 
The  blood  ^nen  seen  ^°  ^e  fi^d  with  very  small  forms  known  as 
cells,  red  blood  cells  or  corpuscles. 

and  white  The  number  of  these  cells  is  so  great  that  a  very 
Small  drop  of  blood  contains  more  than  five  millions,  and  the 
number  contained  in  the  body  of  an  average  man  is  twenty-five 
million  millions,  —  25,000,000,000,000.  In  other  words,  a  man 
has  in  his  body  more  than  twelve  thousand  times  as  many 
individual  blood  cells  as  there  are  people  on  the  earth.  The 
blood  cells  are  so  small  that  it  takes  from  2500  to  3500  to  make 
a  row  an  inch  long ;  but  their  number  is  so  great  that  the  blood 
cells  of  a  man  arranged  in  a  single  row  would  reach  four  times 
around  the  earth.  Spread  out  flat  and  arranged  as  closely  to- 
gether as  possible,  the  red  blood  cells  would  cover  more  than 
half  an  acre. 

Each  of  these  little  cells  is  a  distinct  living  creature,  but  its 


THE  BLOOD 


73 


period  of  life  is  only  about  six  weeks.  Consider  for  a  moment 
the  significance  of  this.  Twenty-five  million  millions  of  blood 
cells  must  be  created  every  six  weeks.  This  requires  the  mak- 
ing of  blood  cells  at  the  rate  of  more  than  seven  millions  per 
second.  At  every  tick  of  the  clock,  seven  million  blood  cells 
die,  on  the  average  ;  and  seven  million  more  must  be  created  to 
take  their  places.  Do  you  see  what  a  wonderful  factory  the 
human  body  is  ? 

A  close  look  at  the  blood  cells  under  a  microscope  will  show 
that  they  are  of  various  shapes  and  sizes.     The  smaller  ones 
are  the  most  numerous. 
They    have    the    shape 
of   flattened,    biconcave 
(concave  on  both  sides) 
disks,  and  are  of  a  faint 
amber  color.     These  are 
the   oxygen   carriers   of 
the  blood. 

They  carry  from  the 
lungs  to  the  tissues  the 

life-giving   OXWen   UDOn 

%  &  J  °  '      .      r 

which  every  function  of 

4.1,       V     J        A  A  T4.    ' 

the  body  depends.     It  is 

by  means  of  a  pigment 

they  contain  called  hemoglobin,  which  gives  to  the  blood  its  red 

color,  that  the  red  cells  are  enabled  to  carry  oxygen.     The  same 

cells  collect  the  poisonous  carbonic  acid  gas  and  carry  it  back  to 

the  lungs  where  it  is  thrown  off. 

The  time  occupied  by  the  passage  of  the  blood  through  the 
lungs  is  very  brief,  only  a  few  seconds;  yet  this  is  sufficient 
for  the  unloading  of  the  poisonous  carbon  dioxide,  which  is  re- 
ceived from  the  tissues,  and  the  taking  on  of  a  fresh  load  of  oxy- 


ARE  TWO  KJNDS  OF  BLOOD  CELLS,  (a)  WHITE 

AND  (6)  RED.   A  SMALL  DROP  OF  BLOOD  CON- 

TAINS  ABOUT  FIVE  MILLION.     SEVEN  MILLION  NEW 

CELLS    ARE  CREATED  EVERY  SECOND.      THE  PICTURE 

SHOWS  GREATLY  MAGNIFIED  CELLS. 


74  KEEPING  THE  BODY  IN  HEALTH 

gen.  The  lungs  may  be  regarded  as  the  chimney  of  the  body,  — 
the  carbonic  acid  gas  is  the  smoke,  and  the  oxygen  is  the  air 
which  comes  in  through  the  draught ;  thus  the  lungs  serve  the 
purpose  of  a  draught  as  well  as  that  of  a  chimney.  Suppose  that 
a  stove  were  constructed  with  but  one  opening  for  the  inlet 
of  air  and  the  outlet  of  smoke.  The  fire  might  be  started  in 
such  a  stove,  but  it  would  quickly  be  smothered  by  the  accumu- 
lation of  smoke,  which  would  prevent  the  entrance  of  fresh  air. 
The  same  thing  would  happen  to  the  body  were  it  not  for  the 
red  blood  cells.  These  carry  in  the  fresh  air,  the  oxygen,  and 
assist  in  carrying  out  the  smoke,  just  as  men  might  carry  into  a 
laundry  buckets  of  pure  water  and  carry  out  the  dirty  water 
resulting  from  the  washing  process. 

The  white  blood  cells  show  many  different  sizes  and  shapes. 
In  the  resting  or  quiet  state,  the  white  cells  are  transparent 
The  white  spherical  forms,  resembling  jelly  drops,  which  float 
blood  cells  m  the  blood  stream.  They  are  able  to  move,  like 
the  amoeba  of  the  pond,  by  changing  their  form,  —  stretching 
themselves  out  into  elongated  shapes  and  gathering  themselves 
together  again  as  a  worm  does. 

The  red  cells  do  not  leave  the  blood  vessels,  but  the  white 
cells  have  the  power  to  pass  through  the  walls  of  the  capillaries, 
leaving  no  gap  or  opening  behind  them.  Just  how  they  accom- 
plish this  is  one  of  the  mysteries  of  science. 

The  white  cells  of  the  blood  have  been  well  called  the  "Army 
of  the  Interior,"  because  they  are  the  defenders  of  the  body 
against  disease  and  other  dangers.  Every  human  body  is 
guarded  and  defended  by  a  countless  host  of  these  little  living 
soldiers,  some  of  whom  guard  the  walls  and  fortifications,  while 
others  like  " flying  columns"  move  about  freely  to  spy  out  the 
enemy  and  attack  him  at  whatever  point  he  appears.  They 
seem  to  have  no  generals  and  no  commander-in-chief ,  yet  in  their 


THE  BLOOD  75 

unity  and  harmony  they  might  well  serve  as  a  model  to  the  great 
armies  of  the  world.  They  possess  powers  superior  to  those  of 
the  most  experienced  veteran  of  any  army.  They  never  sleep, 
but  keep  constant  watch  day  and  night  and  seem  to  detect  by 
instinct  the  approach  of  an  enemy.  They  are  able  to  change 
their  form  and  to  assume  the  form  most  suitable  for  their  ob- 
ject. More  wonderful  still,  they  are  able  to  penetrate  the  walls 
of  blood  vessels  and  other  tissues  without  difficulty.  The  law 
of  their  being  is  that  they  must  conquer  or  die,  and  they  fre- 
quently do  lay  down  their  lives  in  great  numbers  to  save  the 
body  which  it  is  their  business  to  defend. 

Each  cell  seems  to  have  a  peculiar  intelligence  by  which  it  is 
unerringly  guided  to  the  place  where  it  is  needed.     Suppose,  for 
example,  a  few  germs  are  introduced  into  some  trans- 
parent tissue  (tissue  one  can  see  through) ,  such  as 

.       ,       ,  PI  fensiveand 

the  web  of  a  frog  s  foot  or  the  wing  of  a  bat.     What  healing 

happens  may  be  noted  with  a  powerful  microscope,  power 
Watching  closely,  one  may  see  the  white  cells  begin-  ofthe 
ning  to  accumulate  on  the  inner  wall  of  the  blood  cells 
vessel,  just  opposite  the  mass  of  germs.     The  cells 
move  more  and  more  slowly,  creeping  carefully  along,  as  one 
often  sees  a  dog  tracking  his  master  or  game  of  some  sort.     By 
and  by  the  moving  mass  of  cells  comes  to  a  stop.     Then  each 
cell  begins  to  push  out  a  tiny  thread  of  its  own  tissue,  thrusting 
it  through  the  wall  of  the  vessel.     Little  by  little,  the  farther  end 
of  the  delicate  filament  which  has  been  pushed  through  the  wall 
grows  larger  and  larger,  while  the  portion  within  the  wall  becomes 
smaller.     After  a  little  time  each  cell  is  found  outside  the  vessel, 
yet  the  vessel  wall  remains  as  perfect  as  before.     Apparently 
each  cell  has  made  a  minute  opening  and  has  then  tucked  itself 
through,  as  one  might  tuck  a  pocket  handkerchief  through  a 
ring. 


76 


KEEPING  THE  BODY  IN  HEALTH 


Once  outside  the  blood  vessel,  the  body  defenders,  moving 
here  and  there,  quickly  discover  the  germs  and  proceed  at  once 
to  devour  them.  This  they  do  by  inclosing  them  or  surround- 
ing them  with  their  own  little  bodies.  If  the  germs  are  few, 
they  may  soon  be  destroyed  in  this  way,  for  the  white  cells  not 
only  swallow  germs  but  digest  them.  If  the  number  is  very 
great,  however,  the  cells  sacrifice  themselves  in  the  effort  to 


WHENEVER  THE  BODY  is  INJURED  OR  is  ATTACKED  BY  GERMS  THE  WHITE  BLOOD  CELLS  COME 

TO  THE   RESCUE   TO  DESTROY  THE   GERMS   OR  HEAL  THE   WOUND. 

destroy  the  germs,  taking  in  more  than  they  are  able  to  digest 
and  destroy.  When  this  occurs,  the  germs  continue  to  increase ; 
more  white  cells  make  their  way  out  of  the  blood  vessels,  and  a 
fierce  and  often  long-continued  battle  is  waged  between  the 
body  defenders  and  the  invading  germs.  From  all  parts  of  the 
body,  white  cells  hasten  to  the  scene  of  the  conflict  until  the 
number  may  be  so  great  as  to  cause  a  swelling  of  the  part  where 
the  battle  is  in  progress.  It  is  in  this  way  that  a  boil  or  an 
abscess  is  formed,  and  the  "pus"  which  is  discharged  consists 


THE  BLOOD  77 

of  the  dead  white  cells  which  have  laid  down  their  lives  in  de- 
fense of  the  body.  The  number  of  cells  which  may  be  sacrificed 
in  such  a  battle,  when  it  is  waged  day  by  day,  may  be  shown 
from  the  fact  that  a  single  ounce  of  pus  may  contain  as  many 
as  100,000,000,000  of  these  fighting  cells  which  have  died  in 
their  efforts  to  repel  the  invading  germs. 

When  any  part  of  the  body  is  injured,  white  cells  accumulate 
in  great  numbers.  They  spread  themselves  over  the  surface 
of  the  wounded  parts  and  dexterously  weave  a  new  fabric  to 
cement  the  ends  of  a  broken  bone  or  to  cover  a  surface  which 
has  been  made  bare.  In  the  formation  of  new  covering  for  a  sur- 
face from  which  the  skin  has  been  removed,  we  see  the  creating, 
healing  process  which  by  means  of  the  blood  is  being  continually 
carried  on  in  the  body. 

If  you  would  like  to  see  this  illustrated,  watch  the  healing 
of  a  cut.  The  blood  forms  a  clot  in  the  opening ;  and  if  you 
could  examine  the  clot  through  a  microscope,  you  would  find  a 
perfect  network  of  little  strings  or  fibers,  like  the  wire  cables  used 
in  the  building  of  a  bridge,  running  from  one  side  of  the  cut 
to  the  other.  Soon  you  would  see,  creeping  out  on  those  threads 
to  begin  the  work  of  repair,  some  thousands  of  white  blood  cells. 
They  build  up  the  blood  vessels  and  nerves  and  fill  up  the 
space  with  new  tissue  to  heal  the  cut. 

Some  of  the  white  cells  act  as  scavengers,  going  through  the 
body  and  gathering  up  materials  that  are  no  longer  of  any  use 
and  conveying  them  to  places  where  the  body  may  get  rid  of 
them.  There  are  various  sorts  of  white  cells,  each  of  which 
probably  has  its  own  special  work  to  do ;  but  this  is  a  question 
concerning  which  very  little  is  known.  Do  you  not  see  how 
really  wonderful  this  body  of  ours  is? 

The  fluid  portion  of  the  blood  in  which  the  cells  float  is  called 
plasma.  This  is  composed  chiefly  of  water  in  which  the  digested 


78 


KEEPING  THE  BODY  IN  HEALTH 


food  elements  are  dissolved.     It  contains  also  gases  and  other 
poisonous  products  discharged  into  it  by  the  tissues. 

It  is  necessary  for  the  activity  of  the  blood  cells  and  the  tissues 
that  the  blood  should  be  in  an  alkaline  condition.  The  degree 
of  alkalinity  of  the  blood  changes  considerably.  The  absorption 


Arter/es 


Veina 


Liver 

^^^•i 

Vein 

WlTH  YOUR  PENCIL,  TRACE  THE  COURSE  OF  A  DROP  OF  BLOOD  FROM  THE  TIME  IT  LEAVES  THE 
RIGHT  HEART  UNTIL  IT  RETURNS  TO  THE  RIGHT  HE  AST  AGAIN.  TELL  WHAT  HAPPENS  TO 
THE  DROP  OF  BLOOD  OR  WHAT  IT  DOES  AT  DIFFERENT  POINTS  IN  ITS  COURSE. 

of  acid  waste  substances  from  the  tissues  lessens  this  alkalinity. 
It  is  also  lessened  by  sedentary  habits,  by  neglect  to  take 
proper  exercise,  by  impure  air,  by  the  use  of  alcohol,  and  in 
various  diseases,  especially  in  diabetes.  Certain  articles  of 
food,  notably  meat,  which  contain  uric  acid,  may  lessen  the 


THE  BLOOD  79 

alkalinity  of  the  blood.  This  is  a  matter  of  great  importance, 
for  the  reason  that  the  blood  plasma,  like  the  white  corpuscles, 
when  in  a  state  of  health  has  the  power  to  destroy  germs.  But 
when  its  alkalinity  is  lessened  by  the  causes  mentioned,  this  power 
is  to  some  extent  lost.  As  a  result,  the  power  of  the  body  to 
defend  itself  against  intruding 
germs  is  actually  destroyed. 

We  have  seen  that  the  blood  Vena  Cgva. 
is  the  carrier  for  the  body, 
and  therefore  it  must  be  kept 
in  constant  motion.  It  used 
to  be  thought  that  the  blood 
simply  moved  back  and  forth 
in  the  blood  vessels,  as  the 
waters  of  the  sea  ebb  and  flow. 
But  in  1621  an  English  phy- 
sician, named  William  Harvey, 
discovered  that  the  blood  cir- 
culates, flowing  in  the  blood  THERE  is  A  RIGHT  HEART  AND  A  LEFT  HEART. 

WHY  is  SUCH  AN  ARRANGEMENT  NECES- 
VeSSels  like  a  Stream,  always  in        SARY?    NOTICE  HOW  WELL  THE  HEART  is 

one  direction,  and  returning  to      ^PVL?IED    WIIH  AEIEEIES  *"   VEINS' 
its  source,  or  starting  place. 

It  has  been  shown  by  experiments  upon  animals  that  all  the 
blood  in  the  body  passes  through  the  various  organs  hundreds 
of  times  in  the  course  of  a  single  day.     By  what  The  heaft 
wonderful  machinery  is  this  rapid  and  constant  cir-  and  the 
culation  of  the  blood  accomplished?  blood 

The  chief  power  which  causes  the  circulation  of  1 
the  blood  is  the  beat  of  the  heart.     Some  organs  of  the  body 
perform  several  different  kinds  of  work;    but  the  heart  has  a 
single  purpose,  —  that  of  keeping  the  living  stream  of  life  always 
flowing  through  the  body,  bathing  every  cell  and  tissue,  feeding 


8o 


KEEPING  THE  BODY  IN  HEALTH 


every  organ,  washing  away  waste  particles,  and  carrying  them 
to  the  outlets  of  the  body. 

The  heart  is  a  hollow  muscle  about  the  size  of  the  fist,  situ- 
ated just  behind  and  to  the  left  of  the  upper  and  middle  portion 
of  the  breast  bone.  Its  shape  is  conical.  As  it  contracts,  its 
apex  taps  the  chest  wall  at  a  point  just  below  the  fifth  rib,  where 
its  movements  can  be  felt  easily. 

The  heart  is  double ;  or,  rather,  there  are  two  hearts,  a  right 
heart  and  a  left  heart,  almost  identical  in  form.  There  are 
valves  in  the  heart,  very  similar  to  those  in  a 
pump,  so  arranged  that  when  the  heart  con- 
tracts, emptying  itself,  the  blood  forced  out 
cannot  return.  A  very  ingenious  check-valve 
arrangement  relieves  the  heart  of  the  pressure 
of  the  blood  which  has  been  forced  out  of  it, 
as  you  can  see  in  the  illustration. 

By  placing  the  ear  at  a  point  below  someone's 
fifth  rib,  about  two  inches  to  the  left  of  the 
breastbone,  where  the  heart  movements  are 
felt,  one  may  hear,  every  time  the  heart  beats, 
two  distinct  sounds,  which  resemble  the  sylla- 
bles, "lub-dup."  These  sounds  are  produced 
WHY  by  the  movement  of  the  heart  and  the  closure 
of  its  valves,  and  are  like  the  thumping  and 
clicking  sounds  which  accompany  the  action  of  a  water  pump. 
The  organs  used  in  the  circulation  of  the  blood  are  not  con- 
fined to  the  chest  alone,  but  extend  throughout  the  whole  body. 
They  consist  of  the  central  part,  or  heart,  and  two  sets  of 
branching  tubes  connected  with  it.  One  of  these  sets  of  tubes 
starts  at  the  right  heart,  the  other  at  the  left  heart.  The  system 
which  begins  at  the  left  heart  extends  throughout  the  body, 
ending  at  the  right  heart;  the  one  which  begins  at  the  right 


HERE 


THE  VEINS. 


THE   BLOOD  8l 

heart  is  distributed  to  the  lungs  only  and  ends  at  the  left  heart, 
as  shown  in  the  picture. 

In  each  set  of  tubes  there  is  a  main  tube  starting  out  from 
the  heart,  dividing  into  many  branches,  which,  after  becoming 
very  small,  combine  to  form  larger  ones,  finally  making  large 
trunks,  which  again  join  the  heart.  The  tubes  leading  out 
from  the  heart  are  called  arteries;  those  which  lead  back  to  the 
heart  are  called  veins.  The  minute  vessels  which  join  the 
arteries  and  the  veins  are  called  capillaries. 

The  walls  of  the  arteries,  and  to  some  extent  also  the  walls 
of  the  veins,  are  muscular  and  hence  are  able  to  contract.  The 
walls  of  the  arteries  and  veins  are  thick  and  strong;  the  walls 
of  the  capillaries,  however,  are  extremely  thin,  far  more  delicate 
than  the  finest  gossamer  silk.  They  are  transparent,  so  that  by 
placing  under  a  microscope  a  bit  of  thin  tissue,  like  the  web  of 
the  foot  of  a  living  frog,  one  may  easily  see  the  blood  moving 
through  these  minute  vessels  and  may  study  their  rhythmical 
contractions.  By  means  of  the  X-ray  it  is  also  possible  to  study 
the  movements  of  the  heart. 

The  left  heart  works  to  supply  the  body  with  blood  for  the 
building  up  of  its  tissues.     The  right  heart  works  for  the  purpose 
of  pumping  the  blood  which  has  gathered  up   the  The  three 
poisonous  wastes  from  the  tissues  to  the  lungs  for  systems  of 
purification.     The  blood  that  goes  from  the  left  side  of  circulation 
the  heart  through  the  arteries  is  returned  through  the  veins  to  the 
right  side.    It  is  then  pumped  to  the  lungs  by  the  right  heart,  and, 
after  purification,  it  is  returned  from  the  lungs  to  the  left  heart. 

The  blood  thus  passes  through  two  circuits;  the  larger  of 
these,  starting  with  the  left  side  of  the  heart  and  ending  with 
the  right  side,  is  termed  the  systemic  circulation;  the  smaller, 
starting  out  from  the  right  heart  and  ending  with  the  left  heart, 
is  called  the  pulmonary,  or  lesser,  circulation. 


82 


KEEPING  THE  BODY  IN  HEALTH 


Each  heart  is  divided  into  two  compartments,  one  which 
receives  the  blood  and  one  which  sends  it  out.  The  receiving 
compartment  is  called  the  auricle,  from  its  resemblance  to  an 
ear;  the  compartment  which  forces  out  the  blood  is  called  the 
ventricle. 

A  volume  of  blood  equal  to  the  total  amount  contained  in  the 
body  passes  through  each  side  of  the  heart  about  once  every 

minute.  Some  por- 
tions of  the  blood, 
however,  complete  the 
circuit  in  about  half 
this  time.  The  blood 
travels  in  the  arteries 
very  rapidly,  but  in 
the  capillaries  the 
blood  movements  are 
so  slow  as  to  be  almost 
unnoticeable.  The 

THESE  DIAGRAMS  SHOW  THE  ACTION  OF  THE  VALVES  OF    length   of   the   capilla- 

THE    HEART. 

nes,    however,    is    so 

very  short  that  the  time  occupied  in  passing  through  them  is  brief. 
It  has  been  calculated  that  the  capillaries  of  the  body  can  hold 
several  times  as  much  blood  as  the  arteries.  This  partly  accounts 
for  the  slow  movement  of  the  blood  in  the  capillaries. 

The  blood  travels  much  more  slowly  in  the  veins  than  in  the 
arteries.  Its  force  in  the  veins  is  also  very  much  less,  a  condi- 
tion which  accounts  for  the  fact  that  when  a  vein  is  cut  the 
blood  flows  with  a  slow,  steady  stream ;  whereas  when  an  artery 
is  severed  the  blood  spurts  out  in  jets  arid  with  considerable  force. 
The  veins  differ  from  the  arteries  in  that  they  are  supplied 
at  various  points  with  check  valves,  which  prevent  a  backward 
movement  of  the  blood,  as  shown  in  the  illustration  on  page  80. 


Positions  of  valves  before 
the  contraction  of  the  ven- 
tricle 


Position  of  valves  at  the 
beginning  of  the  contrac- 
tion of  the  ventricle. 


EVERY  PART  OF  THE  BODY  is  SUPPLIED  WITH  ARTERIES  AND  VEINS.      IN  THE  PICTURE 

SHOW    WHERE    THE    BLOOD    STARTS    FROM    IN    ITS    COURSE    ABOUT    THE    BODY.        DOES    IT 
ALL   COME    BACK   TO   THE    SAME   I  LACE    SOONER   OR   LATER? 


84  KEEPING  THE  BODY  IN  HEALTH 

The  blood  of  the  pulmonary  or  lung  circulation  starts,  as  we 
have  learned,  from  the  right  heart  and  goes  to  the  lungs  for  puri- 
fication. In  the  lungs,  the  blood  is  spread  out  in  a  fine  capillary 
network,  distributed  in  the  membrane  lining  the  air  passages 
and  air  cells,  and  extending  over  an  area  which  has  been  cal- 
culated to  be  about  one  thousand  square  feet.  After  passing 

Vein 

Artery 


THE   CAPILLARIES  ARE    THE.  CONNECTING   LINKS   BETWEEN   THE   ARTERIES   AND   THE   VEINS. 
WHY  DOES  THE  COLOR  OF  THE  BLOOD  CHANGE  AS  IT  PASSES  THROUGH  THE  CAPILLARIES? 

through  the  lungs,  the  blood  is  returned  to  the  left  heart  to  be 
sent  throughout  the  body  again.  So  it  goes  on  hour  after  hour, 
day  after  day,  and  year  after  year,  as  long  as  one  lives. 

The  portal  circulation  is  a  remarkably  interesting  arrange- 
ment of  blood  vessels  connected  with  the  digestive  organs  and 
The  portal  the  liver.  The  blood  which  is  supplied  to  the  stomach 
circulation  and  intestines  and  other  organs  connected  with  the 
work  of  digestion,  on  entering  the  veins,  does  not  return  at  once 
to  the  right  heart,  as  does  the  blood  from  other  parts  of  the  body, 
but  is  carried  to  the  liver,  in  which  it  is  again  distributed  through 
a  set  of  capillaries  so  that  it  may  be  brought  into  contact  with 
the  living  cells  of  the  liver.  The  liver  cells  are  thus  afforded 


THE  BLOOD 


Lymph 
~G/ands 


an  opportunity  to  remove  impurities  that  may  have  been  ab- 
sorbed from  stomach  or  intestines  and  also  to  act  upon  the  several 
elements  of  the  food.  This  gives  the  liver  an  opportunity  to 
change  the  sugar  that  has  been  digested  into  glycogen  and  to 
store  it  up  for  use  as  body  fuel  and  also  to  deal  with  the  surplus 
protein  which  may  have  been 
eaten,  by  turning  it  into  waste 
for  the  kidneys  to  eliminate. 

The  thin  walls  of  the  capil- 
laries permit  the  escape  of  a 
considerable  portion  of  the 
blood  into  the  tissues.  In 
other  words,  there  is  a  con- 
stant leakage  from  the  blood 
vessels.  This  escaped  blood  L*ctea/_ 
is  called  lymph. 

The  lymph  is  the  means  of 
communication,   or  "  middle- 
man/'   as    it    has 
The  lymph 

been     called,     be- 
tween   the    tissues    and    the 

blood.      All    the     cells    of    the    THE  LYMPHATIC  GLANDS  GATHER  UP  THE  BLOOD 

I,  1        „  i         i       •          i  i  ELEMENTS  THAT  ESCAPE  THROUGH  THE  CAPIL- 

body  are   bathed   in   lymph.       LARIES<    THE  GLAND3  ACT  As  FILTERS,  DE_ 

They  live  in   lymph   just  as  a        TAINING  GERMS  so  THAT  THE  WHITE  CELLS 

.  .  MAY  DESTROY  THEM. 

fish  lives  in  water  or  as  the 

body  as  a  whole  lives  in  the  air.  They  take  up  from  the  lymph 
the  nourishing  substances  which  escape  into  it  from  the  blood, 
and  discharge  into  it  their  waste  matters. 

The  pressure  within  the  blood  vessels  prevents  a  return  of 
the  lymph  into  the  circulation.  Consequently,  particular  pro- 
vision is  made  for  the  gathering  up  of  these  escaped  blood  ele- 
ments into  a  special  set  of  vessels  called  the  lymphatic  system. 


86 


KEEPING  THE  BODY  IN  HEALTH 


There  are  located  along  the  lymph  vessels  at  certain  points  small 
bodies  called  lymphatic  glands.  The  vessels  do  not  pass  through 
these  glands,  but  empty  themselves  into  the  glands  which  are 
drained  by  vessels  on  the  opposite  side.  The  lymph  is  therefore 
passed  along  from  one  to  another  of  a  series  of  glands,  until  it 
nnally  reaches  a  point  in  the  center  of 
the  body  near  the  heart,  where  the  vari- 
ous lymphatic  vessels  converge  and  dis- 
charge their  contents  into  the  large  veins. 
Germs  which  enter  the  body  through 
the  skin  and  find  their  way  into  the 
lymphatics  cannot  reach  the  The  t,attle 
deeper  and  vital  parts  of  the  in  the 
body  without  "  running  the  lymph 
gantlet"  of  many  lymphatic  glands 
glands,  which  act  as  filters,  detaining  the 
germs  and  giving  the  white  cells  of  the 
blood,  which  are  always  present  in  these 
parts  in  great  numbers,  an  opportunity 
to  destroy  them.  The  lymphatic  glands 
are  placed  in  great  numbers  in  those 
parts  of  the  body  where  germs  are  likely 
to  enter.  It  is  for  this  reason  that  they 
are  so  numerous  about  the  neck. 

Having  studied  the  several  routes  by  which  the  blood  travels 
in  the  body,  we  may  next  notice  how  it  is  made  to  travel  along 
How  the  these  channels.  The  impulse  is  given  to  the  blood 
blood  is  movement  by  the  heart,  which  contracts  with  suffi- 
circulated  cient  force  to  elevate  the  blood  to  a  height  of  several 
feet  in  a  tube  connected  with  a  main  artery.  The  total  amount 
of  work  done  in  twenty-four  hours  by  the  heart  of  the  average 
man,  in  its  contractions,  is  equivalent  to  lifting  one  hundred 


A     LYMPH     GLAND      IS      HERE 
SHOWN   GREATLY   ENLARGED. 


THE  BLOOD 


and  twenty-four  tons  one  foot  high,  or  to  lifting  a  hundred- 
weight one  foot  high  2480  times,  or  four  times  a  minute  for  ten 
hours. 

Even  the  expenditure  of  this  amount  of  energy  is  not  sufficient 
to  maintain  the  movement  of  the  blood  current.     Other  forces 
are  brought  into  operation 
which  greatly  assist  this 
important  work.    The  cir- 
culation is  aided  by  the 
rhythmical     contractions 
of  the  small  arteries  and 
capillaries,  which  force  the 
blood  onward  in  a  steady 
stream    into     the    veins. 
The    movements    of    the 
body   produced    by  con- 
tractions     of      the      large    THE  LYMPH  is  THE  "MIDDLEMAN"  BETWEEN  THE 
muscles  of  the  limbs  and 

trunk  aid  the  circulation  by  compressing  the  veins  and  thus 
forcing  the  blood  forward ;  a  return  flow  is  prevented  by  the 
valves  of  the  veins.  The  breathing  movements,  as  we  shall 
see  later,  produce  a  sort  of  suction  action  in  the  chest  which 
draws  the  blood  toward  the  heart. 

The  beating  of  the  pulse  goes  on  steadily  from  birth  to  death 
without  any  interruption.  How  is  this  possible,  since  the  heart 
is  a  muscle  and  the  muscles  require  rest?  An  explanation  is  to 
be  found  in  the  fact  that  the  heart  takes  a  short  rest  at  the  end 
of  every  beat.  A  careful  study  of  its  action  shows  that  it  spends 
nearly  half  its  time  resting. 

The  rate  at  which  the  heart  works  varies  with  many  condi- 
tions. On  counting  the  pulse  at  the  wrist,  the  ordinary  rate  in 
an  adult  sitting  upright  is  found  to  be  68  beats  in  a  minute. 


88  KEEPING  THE  BODY  IN  HEALTH 

In  the  same  person  lying  down  the  pulse  rate  will  be  found  to 
be  64  beats,  and  in  the  same  person  standing  the  rate  will  be 
increased  to  78.  Why  this  change?  Walking  at  a  moderate 
rate  usually  raises  the  pulse  to  about  100,  and  by  running  and 
other  violent  exercise,  it  may  be  increased  to  180  or  even  more. 
The  pulse  rate  of  an  infant  is  130  to  140;  that  of  a  child  of  ten 
years,  90.  In  aged  persons  the  pulse  rate  is  found  to  be  from 
five  to  ten  beats  faster  than  in  middle  age.  In  fever  the  pulse 
rate  is  increased  one  fourth  or  more  and  is  sometimes  even 
doubled. 

The  blood  supply  of  the  body  in  general  is  regulated  by  the 
heart ;  but  each  particular  part  of  the  body  also  requires  some 
How  the  special  regulation  of  the  quantity  of  blood  supplied 
blood  to  it.  This  is  brought  about  by  means  of  nerves  sim- 

supply  is  iiar  to  those  which  control  the  action  of  the  heart. 
Through  the  influence  of  these  nerves,  the  muscular 
walls  of  the  blood  vessels  are  made  to  contract  or  dilate  as  may 
be  necessary.  If  more  blood  is  required,  the  vessels  dilate,  thus 
widening  the  channel  and  increasing  the  supply.  If  less  blood 
is  needed,  the  vessels  contract,  thus  diminishing  the  size  of  the 
channel  through  which  the  blood  must  flow.  These  nerves  are 
brought  into  action  when  cold,  heat,  friction,  or  other  stimulants 
are  applied  to  the  skin. 

Cold  causes  contraction  of  the  walls  of  the  blood  vessels; 
while  heat  and  friction  or  other  irritants  dilate  them.  The  con- 
traction from  the  effect  of  the  cold,  however,  is  quickly  followed 
by  a  dilatation,  or  so-called  reaction.  The  dilatation  produced 
by  cold  differs  from  that  caused  by  heat,  in  that  it  is  more 
permanent  and  is  accompanied  by  an  active  movement  of  the 
arteries,  whereby  an  increased  amount  of  blood  is  pumped 
through  the  dilated  vessels.  Heat  apparently  dilates  the  veins 
more  than  the  arteries  and  does  not  increase  the  activity  of  the 


THE  BLOOD  89 

blood  current  through  the  skin.  It  is  for  this  reason  that  heat 
gives  to  the  skin  a  dusky  red  hue,  while  the  reaction  produced 
by  a  short  application  of  cold  produces  a  crimson  red  color. 
Prolonged  cold  produces  a  bluish  color,  by  so  contracting  the 
small  vessels  that  the  movement  of  the  blood  through  the  skin 
is  almost  entirely  prevented.  The  little  blood  that  remains  in 
the  veins  becomes  so  thoroughly  charged  with  carbonic  acid 
gas  that  it  acquires  a  deep  blue  color,  which  gives  the  blue  tinge 
to  the  skin.  Why  are  your  hands  red  after  they  have  been  used 
in  snowballing,  and  blue  when  they  are  numb  with  cold  ? 

HEALTH  PROBLEMS 

1.  For  purposes  of  experiment,  tie  a  string  tightly  around  your  finger 
and  leave  it  there  for  a  few  minutes.     Describe  what  happens  to  the  ex- 
tremity of  the  finger.     Suppose  the  string  should  be  left  there  permanently ; 
what  would  happen  to  the  finger?     Why? 

2.  Show  why  it  is  proper  to  speak  of  the  white  blood  cells  as  the  "Army 
of  the  Interior." 

3.  Mention  some  of  the  common  enemies  of  the  bod)'-  that  would  de- 
stroy it  if  the  white  blood  cells  were  not  always  on  guard  and  in  good  fight- 
ing condition. 

4.  What  is  the  meaning  of  sedentary  ?    Mention  any  sedentary  habits 
that  persons  have  whom  you  know.     What  do  such  persons  need  to  do  in 
order  to  keep  in  good  health? 

5.  Mention  some  fluids  that  are  alkaline.    How  can  you  tell  whether 
they  are  alkaline  or  not  ? 

6.  Locate  your  heart  precisely.     Point  out  exactly  where  it  "taps  the 
ribs." 

7.  Suppose  the  valves  of  the  right  heart  should  become  weakened,  what 
would  happen  to  the  body?     Suppose  the  valves  in  the  left  heart  should 
become  weakened,  what  would  happen? 

8.  Can  you  illustrate  the  arteries,  veins,  and  capillaries  in  your  body 
by  comparison  with  the  streets  of  your  city?    Are  there  any  streets  that 
you  might  call  arteries,  others  capillaries,  and  others  veins?    Why?    Can 
you  speak  of  arteries,  capillaries,  and  veins  in  a  plant  or  a  tree?    Why  ? 


90  KEEPING  THE  BODY  IN  HEALTH 

9.  Why  are  the  capillaries  so  fine?    Why  should  they  not  be  so  large 
as  veins? 

10.  Does  the  heart  work  harder  in  a  man  seven  feet  tall  than  in  one  four 
feet  tall?    Explain. 

11.  Why  does  the  heart  work  faster  when  one  is  climbing  stairs  or  running 
than  when  he  is  standing  still  or  sitting  ? 

12.  Show   the  checks  in  your  own  veins.    Which  way  with  regard  to 
the  heart  do  you  have  to  push  the  blood  in  order  to  show  these  veins  ? 
Why? 

13.  When  one's  feet  are  cold  or  when  he  has  a  headache,  why  does  he 
take  a  hot  foot  bath?    Why  should  one  take  a  cold  shower  bath  immedi- 
ately after  a  hot  bath? 

14.  Write  a  story  entitled  "The  Traveling  Market"  to  show  all  the 
work  that  is  performed  by  the  blood. 

REVIEW  QUESTIONS 

1.  What  is  it  that  maintains  the  life  of  the  tissues  of  the  body? 

2.  Are  the  cells  that  compose  any  organ  constantly  changing  ?    How  do 
we  know? 

3.  What  is  the  carrier  of  the  body?    What  does  it  carry,  and  where 
does  it  carry  it  ? 

4.  What  is  the  meaning  of  corpuscle  ? 

5.  How  many  blood  cells  in  a  drop  of  blood? 

6.  If  all  the  blood  cells  in  the  body  were  put  together  in  a  row  how  long 
a  line  would  they  make  ? 

7.  How  rapidly  are  blood  cells  made  in  the  body? 

8.  How  do  the  red  blood  cells  look  under  a  microscope  ?    What  is  their 
function? 

9.  How  do  Ae  white  blood  cells  look  under  a  microscope?    What  is 
another  name  for  the  white  blood  cells  ?    What  is  their  function  ? 

10.  Suppose  there  are  not  enough  white  blood  cells  in  the  body  when  it 
is  attacked  by  germs,  what  may  happen? 

11.  How  is  a  boil,  an  abscess,  or  pus  formed? 

12.  How  does  the  blood  heal  wounds  ? 

13.  Describe  the  work  of  the.  plasma. 

14.  What  is  the  meaning  of  "  circulation  of  the  blood?  "    How  is  circula- 
tion caused? 


THE  BLOOD  gi 

15.  How  many  times  does  the  blood  in  the  body  pass  through  the  differ- 
ent organs  ? 

16.  Describe  the  heart,  telling  about  its  shape,  its  parts,  and  its  work. 

17.  What  is  an  artery ?    A  vein?    A  capillary? 

18.  What  is  the  systemic  circulation?    The  pulmonary? 

19.  Why  does  the  blood  travel  more  slowly  in  the  veins  than  in  the 
arteries  ? 

20.  What  arrangement  has  Nature  made  to  prevent  the  blood  in  the 
veins  from  flowing  back  into  the  arteries? 

21:   Why  is  all  the  blood  sent  to  the  lungs? 

22.  Why  is  some  of  the  blood  sent  to  the  liver? 

23.  What  is  the  lymphatic  circulation? 

24.  What  are  the  lymphatic  glands?    What  is  their  use  in  the  body? 
What  is  the  necessity  for  these  glands  ? 

25.  What  helps  the  heart  to  circulate  the  blood? 

26.  How  frequently  does  the  pulse  beat  in  an  average  adult  (a)  when  he 
is  sitting  upright,  (b)  when  he  is  standing,  (c)  when  he  is  walking,  (d)  when 
he  is  running  rapidly? 

27.  How  is  the  blood  supply  controlled  so  that  any  organ  will  get  just 
the  amount  it  needs? 


CHAPTER  VII 

PURE  BLOOD  AND  A  SOUND  HEART 

THE  life  of  the  body  depends,  as  we  have  seen,  upon  the  blood. 
The  condition  of  the  blood  is  therefore  a  matter  of  the  greatest 
The  im-  importance.  Upon  its  purity  depend  not  only  the 
portance  of  nutrition  of  the  body  but  the  power  of  the  body  to 
blood  resist  diseases  of  all  kinds.  Impure  blood  is  the 

cause  of  a  large  proportion  of  the  diseases  from  which 
human  beings  suffer. 

The  prompt  healing  of  a  cut  or  wound  is  evidence  of  clean, 
pure  blood.  When  the  skin  is  broken,  germs  are  admitted  to 
the  tissues,  from  which  they  are  ordinarily  kept  out  by  the  skin. 
If  the  tissues  are  kept  in  .a  healthy  state  by  pure  and  vigorous 
blood,  the  few  germs  that  enter  are  quickly  destroyed,  and  there 
is  no  infection ;  but  when  the  blood  is  not  pure,  the  cells  and  the 
blood  are  not  able  to  make  .the  active  defense  necessary.  So 
the  germs  multiply,  suppuration  (the  making  of  pus)  occurs, 
and  the  wound  may  take  a  long  time  to  heal.  It  is  thus  clear 
that  one's  blood  cells  should  be  kept  in  good  fighting  condition, 
so  that  they  may  have  power  to  resist  and  destroy  germs.  We 
owe  our  protection  or  recovery  from  infectious  diseases  of  all 
sorts  largely  to  the  activity  of  these  wonderful  little  fighters. 

It  has  been  said  that  "all  life  is  under  water."  The  cells  of 
the  body  are  bathed  in  the  lymph  which  drains  out  from  the 
blood  vessels.  If  the  blood  is  impure,  every  cell  and  fiber  of 
the  body  is  bathed  by  an  impure  fluid,  and  must  be  more  or  less 
injured. 

92 


PURE  BLOOD  AND  A  SOUND  HEART        93 

Picture  in  your  mind  a  glass  globe  filled  with  water,  with 
fishes  swimming  about  in  it.  Imagine  that  indigo,  ink,  or  some 
other  kind  of  coloring  matter  is  dropped  into  the  water.  All 
the  water  will  at  once  become  tinged,  and,  if  the  coloring  matter 
is  poisonous,  the  fishes  will  soon  show  signs  of  uneasiness ;  and, 
unless  they  are  relieved  by  the  water's  being  changed,  they  will 
soon  die.  This  illustrates  the  condition  of  the  living  cells  of 
the  body  when  bathed  in  impure  blo'od.  Every  cell  is  injured 
by  the  impurities  brought  in  contact  with  it. 

You  see  now  why,  as  you  have  already  learned,  all  substances 
containing  poisons,  such  as  alcoholic  drinks,  and  such  drugs  as 
opium  and  tobacco,  injure  the  blood  and  lessen  its  defensive 
power.  When  alcohol  is  taken  freely,  the  blood  loses  in  part 
its  power  to  carry  oxygen.  This  accounts  for  the  bluish  appear- 
ance of  the  face,  nose,  and  lips  of  an  "alcoholic,"  or  one  who 
drinks  a  good  deal  of  whisky,  beer,  or  the  like.  Irritating  sub- 
stances such  as  pepper  and  mustard,  and  tea  and  coffee,  which 
contain  caffein,  are  also  injurious  to  the  blood. 

Eating  too  much  and  especially  eating  an  excess  of  meat  will 
render  the  blood  impure  by  filling  it  with  unused  materials, 
which  must  be  treated  as  waste  matter. 

Overwork,  and  lack  of  sleep  render  the  blood  impure  because 
the  body  is  not  able  to  get  rid  of  the  waste  tissue  or  poisons 
which  form  in  large  quantities  when  the  body  is  at  work.  The 
work  of  repair  in  the  body  is  more  active  during  sleep  than  dur- 
ing waking  time.  The  red  cells  of  the  blood  which  are  worn  out 
are  then  replaced,  and  thus  the  red  color  of  the  blood  is  main- 
tained. If  one  does  not  sleep  well,  this  repair  of  the  blood  does 
not  take  place  so  perfectly. 

Neglect  to  maintain  the  right  activity  of  the  organs  that  get 
rid  of  wastes  —  the  lungs,  the  kidneys,  and  the  bowels  —  allows 
these  waste  matters  to  accumulate  in  the  blood,  and  make  it  im- 


94  KEEPING  THE  BODY  IN  HEALTH 

pure.  If  the  lungs  are  not  rendered  active  by  proper  exercise,  the 
blood  will  not  get  a  sufficient  amount  of  oxygen  to  burn  up  the 
wastes,  and  these  will  get  into  the  skin  and  other  tissues,  and 
will  produce  a  dull,  muddy  complexion  and  other  signs  of  im- 
purity of  the  blood. 

When  the  colon  is  not  cleared  regularly  the  poisonous  matters 
which  are  retained  are  absorbed  into  the  blood  and  they  may 
become  a  source  of  disturbance  and  injury  throughout  the  body. 
If  a  sufficient  amount  of  water  is  not  taken  to  dilute  the  blood, 
wash  the  tissues,  and  assist  the  kidneys  in  removing  the  acid 
poisons  which  it  is  their  particular  duty  to  separate  from  the 
blood,  these  injurious  substances  are  retained  and  give  rise  to 
headache,  gout,  and  other  maladies. 

The  idea  that  the  blood  may  be  purified  by  drugs  of  any  sort 
is  a  great  error,  which  has  been  the  cause  of  much  mischief. 
How  to  There  are  no  herbs  nor  drugs,  the  taking  of  which 
purify  the  will  purify  the  blood.  Impure  blood  is  purified  not 
blood  by  putting  something  into  it  but  by  taking  something 

out  of  it.  Water  is  the  universal  cleansing  agent,  and  its  free 
use  is  necessary  for  blood  purification.  It  washes  the  tissues, 
dilutes  the  blood,  and  encourages  the  kidneys  to  remove  wastes. 
To  undertake  to  purify  the  blood  by  means  of  pills  is  about  as 
reasonable  as  to  undertake  to  cleanse  a  soiled  garment  by 
soiling  it  more. 

Vigorous  exercise  out  of  doors  is  one  of  the  most  important 
means  of  maintaining  blood  purity.  Why? 

An  insufficient  amount  of  food  very  soon  makes  the  blood 
poor  and  thin.  Of  course,  the  blood  must  be  enriched  by  an 
ample  supply  of  pure  foods,  as  well  as  kept  pure  by  the  removal 
of  wastes  and  the  keeping  out  of  unwholesome  materials.  It 
is  not  only  important  to  eat  a  sufficient  amount  of  food,  but 
it  is  equally  important  that  the  food  eaten  should  contain 


PURE  BLOOD  AND  A  SOUND  HEART        95 

the  necessary  amount  of  iron.  The  body  loses  each  day  about 
one  fourth  of  one  grain  of  iron.  This  amount  must  be  taken 
in  the  food  daily  in  order  to  prevent  the  gradual  loss  of  iron, 
which  will  lead  to  a  lessening  of  the  amount  of  blood  and  the 
production  of  a  poor  quality  of  blood  cells. 

Iron  suitable  for  the  use  of  the  body  is  found  in  the  green 
parts  of  plants ;  all  garden  vegetables  and  greens  of  all  kinds, 
such  as  turnip  tops,  spinach,  beet  tops,  dandelions,  and  the 
green  leaves  of  cabbage  and  lettuce,  are  rich  in  iron.  Many 
common  weeds  also  contain  iron,  particularly  purslane,  narrow- 
leaved  dock,  and  redroot,  all  of  which  make  excellent  greens. 
The  yolk  of  an  egg  is  also  rich  in  iron.  Red  meats  contain  iron, 
but  it  is  in  a  form  which  is  not  so  easily  assimilated  as  that  in 
which  iron  is  found  in  vegetable  foods.  Bran  contains  a  generous 
quantity  of  iron.  Iron  is  likewise  found  in  considerable  quan- 
tities in  strawberries  and  other  berry  fruits. 

Care  should  be  taken  to  include  in  each  meal  some  dish  which 
furnishes  iron  in  abundance.  Growing  children  require  twice 
as  much  iron  as  do  adults.  In  general,  foods  which  are  rich  in 
lime  are  also  rich  in  iron.  Milk  is  an  exception  to  this  rule, 
being  rich  in  lime  but  very  poor  in  iron. 

Cold  baths  increase  the  number  of  active  cells  in  the  blood. 
This  has  been  proved  by  actually  counting  the  number  of  cells 
before  and  after  a  bath.  It  must  not  be  supposed  that  the  cells 
added  to  the  blood  are  formed  in  this  short  time.  Cells  which 
have  been  held  idle  are  by  this  means  brought  into  active 
circulation  and  made  useful.  If,  however,  a  cold  bath  is  taken 
regularly  from  day  to  day,  there  is  an  actual  increase  in  num- 
ber of  blood  cells  formed.  In  this  way,  the  cold  bath  increases 
the  resisting  power  of  the  body  and  rallies  the  blood  cells,  so  to 
speak,  calling  them  out  from  their  hiding  places  and  preparing 
them  to  fight  with  vigor  the  battles  that  must  be  waged  every 


96  KEEPING  THE  BODY  IN  HEALTH 

moment  in  defense  of  the  body.  Cold  baths  also  improve  the 
quality  of  the  blood  by  increasing  its  alkalinity.  The  circula- 
tion of  the  blood  is  quickened  and  improved  by  a  cold  bath. 
It  increases  the  force  of  the  heart  beat,  and  deepens  the  breathing, 
so  that  an  increased  amount  of  oxygen  is  taken  into  the  lungs 
for  the  purification  of  the  blood.  But  it  should  be  remembered 
that  one  must  always  react  favorably  to  cold  baths  or  they 
may  injure  him.  That  is,  he  must  feel  warm  and  vigorous 
after  them.  Most  people  cannot  remain  for  along  period  in 
cold  water  without  becoming  chilled  and  perhaps  seriously  in- 
jured. 

In  order  that  the  blood  may  perform  its  work,  it  is  necessary 

not  only  that  it  should  be  rich  in  food  elements  and 
that  affect     ^ree   fr°m   impure   substances,   but   it  must  also  be 
the  heart      circulated  properly  by  a  strong  heart. 
unfavor-  Nature  has  constructed  the  heart  so  that  it  can 

adapt  itself  to  all  the  ordinary  needs  of  life;  and 
if  we  are  careful  not  to  impose  needless  burdens  upon  it,  nor  to 
illtreat  it  in  any  way,  we  may  expect  it  to  do  its  work  well  for 
a  long  lifetime.  If  it  fails  to  do  this,  the  cause  is  usually  some 
fault  for  which  we  are  ourselves  responsible. 

Great  extremes  of  heat  and  cold  are  injurious  to  the  heart. 
Heat  stimulates  it  to  a  high  degree,  while  the  effect  of  cold  is 
to  depress  and  to  weaken  it  and  also  the  small  blood  vessels. 
Hence,  you  see  it  is  of  importance  to  protect  the  body  adequately 
by  adapting  the  clothing  to  the  seasons  and  to  the  needs  of  daily 
life.  It  is  especially  important  to  clothe  the  feet  well,  so  that 
a  proper  balance  of  the  circulation  may  be  maintained.  Many 
of  the  large  veins,  especially  in  the  extremities,  are  located  near 
the  surface,  and  hard  pressure  interferes  with  the  flow  of  blood 
through  them.  For  this  reason,  elastics  on  the  arms  or  legs, 
and  tight  shoes,  belts,  or  collars  are  injurious. 


PURE  BLOOD  AND  A  SOUND  HEART        97 

Very  strong  emotions  affect  the  heart  injuriously.  Violent 
anger  has  sometimes  caused  a  person  to  drop  dead  from  sudden 
heart  failure.  The  lesson  to  be  learned  from  these  facts  is  that 
we  should  keep  the  emotions  and  passions  well  under  control. 
Does  this  mean  we  should  not  be  joyful?  What  does  it  mean? 

The  pulse  of  the  tobacco  user  indicates  unmistakably  the 
injury  which  smoking  does  to  the  heart.  The  heart  loses  its 
firm,  steady  beat  and  is  feeble  and  irregular.  This  condition 
is  so  well  known  that  it  has  received  the  name  "  tobacco  heart." 

Alcohol  injures  the  muscles  of  the  heart  and  the  blood  vessels, 
and  if-  its  use  is  kept  up  it  may  result  in  a  hardening  of  the  walls 


Pulse  beat  of  healthy  person 


Pulse  beat  of  tobacco  user 


Pulse  beat  of  drunkard, 
TOBACCO  AND  ALCOHOL  AFFECT  THE  HEART. 

of  the  arteries,  which  will  bring  on  an  early  old  age.  The 
habitual  use  of  alcohol  causes  the  heart  to  be  overloaded  with 
fat,  which  interferes  with  its  work.  In  some  cases,  its  muscular 
tissue  is  changed  to  fat  and  it  loses  its  strength,  so  that  the  heart- 
beat is  a  mere  flutter.  The  muscular  walls  of  the  small  arteries 
of  the  brain  and  other  parts  are  likely  to  undergo  a  similar  change, 
and  they  may  become  so  weak  that  they  are  not  able  to  resist 
the  pressure  of  the  blood.  Apoplexy  (the  bursting  of  a  blood 
vessel  in  the  brain)  is  more  frequent  among  those  who  use  alcohol 
than  among  abstainers. 


98  KEEPING  THE  BODY  IN  HEALTH 

Alcohol  quickens  the  pulse,  not  by  strengthening  the  heart, 
but  by  affecting  the  nerve  centers  that  control  the  heart  and 
the  small  blood  vessels.  In  consequence,  the  heart  "runs 
away"  as  it  were,  like  a  steam  engine  which  has  lost  its  " gov- 
ernor" or  a  clock  pendulum  from  which  the  weight  has  been 
removed.  The  red  face  and  eyes  so  often  seen  in  a  drunkard 
are  due  to  a  paralysis  of  the  small  blood  vessels,  which  keeps 
them  always  full  of  blood. 

These  things  show  us  that  alcohol  has  an  injurious  effect  upon 
the  heart.  Can  one  afford  to  take  the  risk  of  weakening  this 
wonderful  organ  in  any  way?  In  a  severe  illness,  everything 
depends  upon  the  ability  of  the  heart  to  stand  the  strain  of  the 
disease,  and  if  it  has  been  weakened  from  any  cause,  it  may 
suddenly  fail.  It  has  been  found  that  heavy  beer  drinkers  suc- 
cumb more  readily  to  disease  than  abstainers,  on  account  of  the 
weakened  condition  of  the  heart,  known  as  "beer  drinker's 
heart." 

Many  of  the  headache  remedies  commonly  used  are  manu- 
factured from  coal  tar,  and  these  have  a  very  injurious  effect  on 
the  heart.  Medicine  of  any  kind  should  never  be  taken  except 
by  the  advice  of  a  physician.  Why  ? 

Lack  of  elimination  of  body  wastes  is  a  common  cause  of 
disease  of  the  blood  vessels  —  perhaps  one  of  the  principal 
causes  of  hardening  of  the  blood  vessels  and  premature  old 
age. 

Severe  exercise  may  injure  the  heart  by  placing  too  great  a 
strain  on  it.  Going  to  excess  in  football  or  bicycle  riding,  or 
other  severe  and  long-continued  exercise  may  overwork  the 
heart  and  cause  incurable  disease.  The  heart,  like  any  other 
muscle,  enlarges  by  exercise.  An  enlarged  condition  of  the 
heart  known  as  "athletic  heart"  may  be  caused  by  too  severe 
exercise.  In  this  condition  there  is  trouble  frequently  with  the 


PURE  BLOOD  AND  A  SOUND  HEART 


99 


valves  of  the  heart,  which  do  not  close  completely,  but  allow  a 
leakage  of  the  blood  backward.  This  increases  the  work  of  the 
heart,  as  some  of  the  blood 
must  be  pumped  twice. 

The  heart  is  developed  and 
made  strong  by  exercise,  just 
as  is  any  other  muscle.  The 
size  of  the  heart  is,  as  a  rule, 
proportioned  to  the  amount 
How  to  °f  work  it  habitu- 
strengthen  ally  has  to  perform, 
the  heart  Animals  kept  in 
cages  or  in  captivity  have 
been  found  upon  examination 
after  death  to  have  much 
smaller  hearts  than  those  of 
other  animals  of  the  same 

Species.       Ine  neari  OI    a  race     VERY  HARD  AND  PROLONGED   EFFORT,  AS  IN 

horse  is  much  larger  than  that 
of  an  ordinary  work  horse. 
The  heart  of  a  stag,  a  very 
active  animal,  is,  in  propor- 
tion to  the  size  of  the  animal,  about  twice  as  large  as  that  of  a 
pig  kept  in  a  pen.  Can  you  tell  why  ? 

One  who  has  a  well-developed  and  strong  heart  has  more 
vigor,  more  endurance,  and  more  courage  than  he  otherwise 
would  have.  When  one  not  accustomed  to  daily  active  exercise 
hurries  to  catch  a  train  or  runs  up  a  flight  of  stairs,  he  gets  out 
of  breath  very  easily  and  perhaps  suffers  from  heavy  beating  or 
palpitation  of  the  heart.  Enough  daily  exercise  should  be 
taken  to  keep  the  heart  strong  and  vigorous,  so  that  it  will  not 
be  affected  by  moderate  exertion. 


©  Keystone  View  Co.,  Inc. 


BICYCLE-RIDING,  ROWING,  RACING,  AND  THE 
LIKE,  ARE  LIKELY  TO  OVERTAX  THE  HEART, 
ALTHOUGH  THE  DANGER  WILL  BE  LESSENED 
IF  ONE  TRAINS  GRADUALLY  FOR  GREAT 
EFFORT. 


100  KEEPING  THE  BODY  IN  HEALTH 

The  same  exercise  which  strengthens  the  legs  in  running,  or 
the  arms  in  rowing,  also  strengthens  the  heart  by  forcing  it  to 
do  the  work  necessary  to  pump  the  blood  to  the  active  muscles, 
and  carry  it  to  the  lungs  for  purification. 

One  not  accustomed  to  exercise  should  begin  with  a  little  at  a 


©  Keystone  View  Co.,  Inc. 

THE  HEART  CAN  BE  TRAINED  BY  PROPER  EXERCISE  SO  THAT  IT  WILL  BE  STRONG  AND  CAPABLE 
OF   MEETING   WITHOUT   INJURY   THE   DEMANDS   THAT   ARE   MADE    UPON   IT. 

time,   increasing  the   amount  as   the  heart  becomes  stronger. 
The  effect  on  the  pulse  beat  and  the  breath  will  show  how  much 


PURE  BLOOD  AND  A  SOUND  KEA&T       y,oi 

exercise  it  is  safe  to  take.  Take  a  short  run  of  about  a  minute 
or  a  trot  of  a  few  minutes  ind  notice  the  effect  upon  your  breath- 
ing and  your  pulse.  One  should  avoid  getting  very  much  out 
of  breath  and  exciting  the  heart  to  such  a  degree  as  to  produce 
a  very  rapid  pulse.  Why?  The  shortness  of  breath  occasioned 
by  exercise  should  pass  away  after  a  few  minutes  of  rest  and  the 
pulse  should  also  return  to  its  ordinary  rate.  Outdoor  games 
-swimming,  rowing,  walking,  and  especially  mountain  climb- 
ing  —  are  excellent  forms  of  exercise  for  strengthening  the  heart. 

HEALTH  PROBLEMS 

1.  Can  you  tell  when  you  look  at  a  person  whether  or  not  his  blood  is 
pure  ?    Mention  the  signs  that  indicate  impurity. 

2.  Have  you  ever  noticed  the  eyes  and  skin  of  a  drunkard?    If  so,  do 
they  seem  like  the  eyes  and  skin  of  normal  persons  ?    Why  is  the  end  of  a 
drunkard's  nose  redder  than  it  should  be? 

3.  Can  a  person  who  works  at  a  desk  all  day  and  who  does  not  take 
exercise  in  the  open  air  keep  his  blood  from  becoming  impure?    Explain. 

4.  Should  you  expect  to  find  pure  blood  in  persons  who  live  all  the 
•time  in  a  town  or  city  where  the  sun  is  clouded  because  of  smoke  and  dust  ? 
Explain. 

5.  Many  persons  think  they  have  to  take  blood  purifiers  in  the  spring. 
Why  should  they  feel  the  need  of  such  things  especially  in  the  spring  ?    Do 
you  think  they  can  purify  their  blood  by  taking  such  medicines  ? 

6.  Do  you  think  it  would  be  wise  for  a  weak  person  who  is  not  accus- 
tomed to  cold  baths  to  jump  into  a  tub  of  very  cold  water  or  into  a  cold 
river  or  a  cold  lake  ?    Explain. 

7.  I  know  boys  who  wear  very  tight  belts  to  hold  up  their  trousers. 
Do  you  think  they  are  likely  to  be  injured  in  this  way?    Why? 

8.  Why  are  boys  who  use  tobacco  or  alcohol  not  allowed  to  join  an 
athletic  team  in  a  high  school  ? 

9.  Do  you  know  persons  who  get  out  of  breath  if  they  merely  walk 
rapidly  ?    What  is  probably  the  matter  with  such  people  ? 

10.   Does  one  need  to  take  special  heart  exercises  or  will  the  heart  take 
care  of  itself  if  one  lives  right,  —  that  is,  if  he  takes  enough  food  for  his 


102  KEEPING  THE  BODY  IN  HEALTH 

needs,  exercises  regularly  so  as  to  keep  his  body  and  muscles  in  good  condi- 
tion, refrains  from  putting  poisons  into  his  body,  and  so  on? 

REVIEW  QUESTIONS 

1.  Why  should  blood  cells  be  kept  in  good  fighting  condition? 

2.  Suppose  the  blood  is  impure;    what  happens  to  every  cell  in  the 
body? 

3.  How  do  alcoholic  drinks,  such  as  whisky  and  beer,  affect  the  blood? 

4.  How  does  eating  affect  the  blood?    How  does  sleep  affect  it  ? 

5.  What  will  happen  to  the  blood  if  the  body  does  not  get  rid  of  wastes  ? 

6.  What  organs  have  to  do  mainly  with  getting  rid  of  wastes  ? 

7.  Why  is  water  valuable  in  keeping  the  blood  pure? 

8.  Can  one  make  the  blood  pure  by  taking  pills?    Why?    What  is  the 
only  way  in  which  one  can  make  his  blood  pure  ? 

9.  Mention  all  the  benefits  that  come  from  cold  baths,  if  one  is  strong 
enough  to  take  them. 

10.  Why  is  it  necessary  to  have  a  strong  heart  ? 

11.  Tell  how  these  things  affect  the  heart:     tight    clothing;    strong 
emotions,  as  anger  or  the  like ;  tobacco ;  alcohol ;  very  violent  exercise. 

12.  Why  do  people  who  use  a  good  deal  of  tobacco  and  alcohol  seem  less 
able  to  resist  diseases  than  others? 

13.  How  can  one  strengthen  his  heart  so  that  it  will  be  ready  for  any 
need  of  daily  life? 


CHAPTER  VIII 

THE  BREATH  OF  LIFE 

FROM  what  you  have  already  learned  you  know  that  we 
breathe  to  obtain  the  life-giving  gas  called  oxygen  and  to  expel 
the  poisonous  gas  called  carbonic  acid  or  carbon  oxygen 
iioxide,  which  is  formed  in  all  living  things.  Every  one  the  life- 
of  the  many  millions  of  tiny  living  creatures  or  cells  of  Siving  gfls 
which  the  body  is  made  up  must  breathe  in  order  to  live.  That 
is,  each  cell  must  get  a  constant  supply  of  oxygen  and  must  get 
rid  of  its  carbon  dioxide.  Oxygen  is  therefore  essential  to  life. 
Its  great  use  in  the  body  is  to  set  free  or  bring  into  action  the 
energy  stored  in  the  body  in  the  form  of  digested  and  assimi- 
lated food.  The  body  derives  its  warmth  and  power  to  work 
from  the  burning  of  these  food  substances  in  the  cells.  We 
know  that  the  burning  of  wood  or  coal  in  a  stove  cannot 
take  place  without  oxygen.  If  a  stove  is  made  air  tight  by 
shutting  up  all  the  draughts,  the  fire  will  burn  low  and  after  a 
while  will  go  out  altogether.  Oxygen  is  just  as  necessary  for  the 
burning  of  food,  the  fuel  of  the  body. 

The  cells,  packed  as  they  are  in  the  interior  of  the  body,  can- 
not get  their  oxygen  directly  from  the  air,  as  the  amoeba  can 
from  the  water.  It  must  therefore  be  taken  into  the  body  and 
carried  to  them.  In  the  division  of  labor  among  the  cells,  the 
work  of  taking  into  the  body  the  supply  of  oxygen  needed  by 
the  cells  and  of  expelling  the  carbon  dioxide  formed  by  them  is 
given  to  the  lungs.  Just  as  the  digestive  organs  prepare  the  food 
for  all  the  cells,  so  the  lungs  supply  the  oxygen  for  all  the  cells. 

There  must,  of  course,  be  some  means  of  communication  be- 

103 


IO4 


KEEPING  THE  BODY  IN  HEALTH 


tween  the  lungs  and  the  cells,  by  which  the  oxygen  from  the 
lungs  may  reach  the  cells,  and  the  carbon  dioxide  from  the  cells 
may  reach  the  lungs.  This  is  provided  for  by  the  circulation  of 


Trachea 


Bronchia/ 
Tubes 


THE  OXYGEN  NEEDED  BY  THE  BODY  IS  TAKEN  IN  THROUGH  THE  LUNGS,  AND  CARBON  DIOXIDE, 
WHICH   IS  INJURIOUS   TO   THE   BODY,    IS   EXPELLED   THROUGH   THE   LUNGS. 

the  blood,  which  is,  as  we  have  seen,  a  carrier  between  the  lungs 
and  the  tissues  as  well  as  between  the  digestive  organs  and  the 
tissues. 

The  air  is  admitted  to  the  lungs  by  means  of  a  tube  called 
the  windpipe  or  trachea,  which  at  its  upper  end  is  widened  into 
The  a  small  chamber  called  the  larynx,  a  box  made  of 

breathing  cartilage  in  which  the  vocal  cords  are  placed,  and 
apparatus  which  communicates  with  the  air  through  the  nose 
and  mouth.  At  its  lower  end,  the  trachea  is  divided  into  two 
branches,  called  bronchial  tubes,  one  of  which  passes  to  the  right 
and  one  to  the  left.  Each  of  these  is  divided  and  subdi- 


THE  BREATH  OF  LIFE 


105 


vided  like  the  branches  of  a  tree  into  innumerable  smaller 
tubes  or  bronchi,  the  very  smallest  of  which  are  called  bronchioles. 
The  bronchioles  end  in  small  pouches,  the  sides  of  which  are 
pitted  everywhere  with  little  recesses  or  tiny  sacs  called  air 
cells.  The  total  number  of  air  cells  in  the 
lungs  has  been  estimated  to  be  not  less  than 
1,700,000.  The  term  cell  is  here  used  in  its 
ordinary  sense,  meaning  a  small  chamber, 
and  not  in  the  sense  in  which  we  used  it  in 
previous  chapters.  What  did  it  mean  then  ? 
The  air  cells  and  air  tubes  are  bound  to- 
gether by  means  of  tissues  in  which  there 
are  a  large  number  of  elastic  fibers.  These 
enable  the  lungs  to  stretch  or  expand  when 
they  are  filled  with  air.  The  whole  is  com-  THERE  ARE  ABOUT  1,700,- 

,,.,,.  i  11     j      ,  i  000  OF  THESE  AIR  CELLS 

pletely  inclosed  in  a  membrane  called  the       OR  AIR  SACS   IN  THE 
pleura.  LUNGS-    THE 

The  purpose  of  the  lungs  is,  of  course,  to 
bring  the  blood  into  contact  with  the  air. 
The  lining  membrane  of  the  air  cells  is  of 
such  marvelous  thinness  that  2500  layers  would  make  but  an 
inch  in  thickness.  On  account  of  the  immense  number  of  air 
cells  and  minute  air  tubes,  the  extent  of  this  membrane  is  so 
great  that  if  it  were  spread  out  over  a  flat  surface  it  would  cover 
fully  2000  square  feet.  Immediately  under  this  delicate  mem- 
brane, in  the  walls  of  the  air  cells,  is  a  very  remarkable  network 
of  capillaries,  which  as  you  know  are  minute  blood  vessels. 
The  blood  which  passes  through  this  wonderful  capillary  network 
is,  by  reason  of  the  thinness  of  the  lining  membrane,  exposed 
to  the  air  in  the  most  thorough  manner  possible.  All  the  blood 
in  the  body  passes  through  the  lung  capillaries  once  every  minute 
and  a  quarter. 


LUNGS.  1HE  OXYGEN 
IN  THE  AIR  WE  BREATHE 
PASSES  THROUGH  THE 
WALLS  OF  THE  CELLS 
INTO  THE  BLOOD. 


io6 


KEEPING  THE  BODY  IN  HEALTH 


The  passage  which  leads  to  the  lungs  begins  with  the  mouth 
and  the  nostrils.  The  nostrils  lead  to  the  nasal  cavity.  This 
cavity  is  divided  for  about  one  half  its  length  by  means  of  a 
partition  called  the  septum.  The  sides  of  the  nasal  cavity  are 


t/asa/  Cav/fy 


Opening  of 
Eustacfiian  Tube 

Soft  Pa/ate 


ffardPa/ate 


Trachea 


HERE  TS  SHOWN  THE  PASSAGE  WHICH  LEADS  TO  THE  LUNGS.  THE  ESOPHAGUS  LEADS  TO  THE 
STOMACH.  DO  YOU  WONDER  THAT  FOOD  SOMETIMES  GOES  DOWN  THE  WINDPIPE? 

covered  with  mucous  membrane,  the  extent  of  which  is  greatly 
increased  by  scroll-like  projections  of  bone  and  cartilage  from  the 
outer  walls  of  the  cavity,  as  you  see  in  the  picture.  The  nasal 
cavity  and  the  cavity  of  the  mouth  unite  at  their  back  parts 
to  form  the  pharynx,  which  is  separated  from  the  mouth  by  a 
hanging  partition,  —  the  soft  palate.  Everything  which  enters 


THE  BREATH  OF  LIFE 


107 


Larynx 


the  lungs  or  the  stomach  passes  through  the  pharynx.  On 
either  side  of  the  pharynx  are  the  tonsils,  two  remarkable  glands 
which  are  placed  at  the  entrance  to  the  body  to  protect  it  against 
the  germs  that  are  carried  in  with  air  and  food. 

When  germs  are  present  in  such  great  numbers  that  the  tonsils 
are  not  able  to  destroy  them  all,  some  of  the  germs  penetrate 
the  tissues  and  the  tonsils  become  infected.  The  germs  creep 
down  into  little  crypts  or  pockets,  of  which  the  tonsils  are  full. 
They  sometimes  breed  there  and  fill  these  pockets  with  germs 
as  a  boy  may  fill  his  pocket  with  marbles.  Sometimes  so  many 
germs  cluster  upon  the  tonsils  that  the  tonsils  become  over- 
whelmed and  lose  their  power  to  destroy  the  germs;  the  result 
is  that  the  germs  destroy  the  tonsils.  The  tonsils  then  become 
inflamed  and  enlarged,  and 
quite  frequently  their  removal 
is  necessary.  Infection  from 
diseased  tonsils  may  be  carried 
to  the  lymph  glands  of  the  neck 
and  to  the  lungs ;  and  enlarged 
glands,  rheumatism,  or  even 
tuberculosis  may  result.  In- 
fected tonsils  should  be  re- 
moved. One  of  the  best  means 
of  protecting  the  tonsils  is  by 
breathing  plenty  of  pure,  cold, 
fresh  air.  Dust-laden  air 
should  be  avoided. 

Just  beyond  the  root  of  the     AIR  CANNOT  REACH  THE  LUNGS  EXCEPT  BY 

.         .  11       r  ,i  PASSING  THROUGH  THE  LARYNX,  TRACHEA, 

tongue,  in  the  front  wall  of  the       AND  BRONCHIAL  TUBES. 

pharynx,  is  an  opening  called 

the  glottis,  which  leads  into  the  larynx,  the  entrance  to   the 

windpipe.     The  glottis  is  guarded  by  a  closely  fitting  covering 


io8  KEEPING  THE  BODY  IN  HEALTH 

called  the  epiglottis,  consisting  of  a  leaf -shaped  cartilage,  one  side 
of  which  is  hinged  at  the  root  of  the  tongue  in  such  a  manner 
that,  in  the  act  of  swallowing,  the  cover  is  tightly  closed,  pre- 
venting the  entrance  of  food  or  drink  into  the  windpipe.  The 
pharynx  itself  leads  to  the  esophagus,  or  food  pipe. 

The  whole  of  the  breathing  apparatus  is  lined  with  mucous 
membrane,  which  is  kept  moist  with  mucus.  Particles  of  dust 
and  germs  which  are  carried  down  into  the  air  passages  are 
caught  by  this  mucus,  much  as  flies  are  caught  on  a  sticky  fly 
paper.  Except  in  the  air  cells  and  the  pharynx,  the  walls  of  the 
air  passages  may  be  shown  by  the  microscope  to  be  covered 
with  minute  hairs.  By  the  constant  movement  of  these  hairs,  or 
cilia  as  they  are  called,  a  stream  of  mucus  is  swept  upwards 
towards  the  mouth,  carrying  with  it  the  captured  dust  and  germs. 
In  this  way  the  air  is  cleansed,  and  dust  and  germs  are  in  a 
great  measure  prevented  from  reaching  the  air  cells  of  the  lungs. 

If  you  could  watch  the  blood  as  it  passes  through  the  lung 
capillaries,  you  would  see  a  remarkable  change  taking  place  in 
Wkat  it.  The  dark  purplish  hue  which  it  has  when  it  enters 

takes  the  capillaries  is  changed  to  a  bright  crimson  before 

place  in  it  leaves  them  and  starts  for  the  heart.  What  is  the 
111158  reason  for  this  wonderful  change  of  color?  It  means 
that  there  has  been  an  actual  change  in  the  quality  of  the  blood. 
A  part  of  its  cargo  of  carbon  dioxide  has  been  discharged,  and  a 
fresh  load  of  oxygen  taken  on  by  the  red  cells.  That  is,  as  the 
blood  flows  through  the  capillaries  in  the  lungs,  it  gives  off  car- 
bon dioxide  into  the  air  sacs  and  receives  in  its  place  a  fresh 
supply  of  oxygen. 

In  the  capillaries  of  the  body  you  would  see  the  opposite 
kind  of  change  taking  place.  Here  the  blood  loses  its  bright 
crimson  color  and  takes  on  a  darker  hue.  When  the  blood 
reaches  the  capillaries,  the  oxygen  received  from  the  lungs 


THE  BREATH  OF  LIFE  109 

is  sent  through  the  thin  walls  of  the  vessels  into  the  lymph. 
The  cells  take  up  the  oxygen  from  the  lymph  in  which  they  live 
(just  as  the  one-celled  animal  takes  its  oxygen  from  the  water) 
and  discharge  into  it  their  carbon  dioxide,  which  is  sent  from  the 
lymph  into  the  capillaries.  As  in  the  lung  capillaries  the  blood 
gives  up  carbon  dioxide  and  takes  on  oxygen,  so  in  the  capil- 
laries of  the  other  tissues  the  blood  gives  up  .oxygen  and  takes 
on  carbon  dioxide ;  and  it  is  this  change  which  causes  it  to  darken 
in  color.  For  this  reason  the  blood  in  the  arteries  that  carry 
the  purified  blood  from  the  heart  is  much  brighter  in  color  than 
that  in  the  veins  which  return  the  impure  blood  to  the  heart. 
It  is  this  dark  color  of  the  blood  that  causes  the  veins  that  can  be 
seen  through  the  skin  to  appear  blue. 

The  change  that  takes  place  in  the  blood  in  the  lung  capil- 
laries causes  a  different  sort  of  change  to  take  place  at  the  same 
time  in  the  air  in  the  lungs.  The  process  of  taking  oxygen  out 
and  putting  carbon  dioxide  in  spoils  the  air  and  makes  it  neces- 
sary that  it  should  be  constantly  renewed. 

The  purpose  of  breathing  is  to  ventilate  the  lungs  by  putting 
fresh  air  into  them.     Do  we  at  each  breath  expel  all  the  air  in 
the  lungs  and  take  in  an  entire  new  supply?     Most  HOW  the 
people  change  only  from  one  tenth  to  one  fifth  part  of  lungs  are 
the  air  in  the  lungs  with  each  breath.  ventilated 

The  air  is  brought  into  the  lungs  by  a  most  wonderful  pump- 
ing device.  The  lungs,  with  the  heart,  are  suspended  in  an  air- 
tight box,  —  the  chest  cavity  or  thorax..  The  ribs  with  the 
muscles  and  other  tissues  that  cover  them  form  the  sides  of  the 
thorax.  The  backbone  and  the  chest  bone  also  help  to  form 
the  walls.  The  floor  or  under  side  of  the  cavity  is  formed  by 
a  broad  strong  muscle  called  the  diaphragm,  which  separates 
the  thorax  from  the  abdomen,  the  cavity  which  contains  the 
stomach,  bowels,  and  other  organs. 


no 


KEEPING  THE  BODY  IN  HEALTH 


The  diaphragm  acts  very  much  like  the  piston  of  a  pump.  It 
moves  up  and  down,  pulling  the  air  into  the  lungs  as  it  descends. 
Air  enters  the  lungs  when  the  chest  cavity,  or  thorax,  is 
enlarged.  This  is  accompanied  by  a  downward  movement  of 
the  diaphragm  and  an  outward  movement,  in  all  directions,  of 
the  side  walls  of  the  chest.  This  widening  is  done  by  means 
of  muscles  which  lift  the  ribs  and  pull  them  outward.  When 
these  muscles  cease  their  pulling,  the  chest  walls  return  to  their 
former  position,  and  the  air  which  was  drawn  into  the  lungs  by  the 
enlarging  of  the  chest  is  forced  out  again.  The  natural  elasticity 
of  the  lungs  and  the  contraction  of  the  muscles  of  the  abdomen 
also  aid  in  expelling  the  air.  The  lungs  act  much  like  a  pair  of 
bellows,  except  that  the  air  passes  in  and  out  at  the  same  opening. 
The  windpipe  is  the  nozzle  of  the  bellows,  the  lungs  are  the  pouch, 
and  the  points  of  the  ribs  on  either  side,  the  two  handles.  When 
the  muscles  contract,  the  points  of  the  ribs  are  separated,  just 
as  the  handles  of  a  pair  of  bellows  are  drawn  apart.  This  may 
easily  be  seen  in  the  panting  of  a  dog,  or  in  the  breathing 

of  a  long-distance 
runner.  The  dia- 
phragm may  be 
compared  to  the 
piston  of  a  pump, 
since  it  moves  up 
and  down  helping 
to  draw  air  into 
the  lungs  as  it 
descends  and  to 
force  air  out  as 
it  rises. 

There  are,  as  you  can  see,  two  acts  in  breathing.     The  first, 
or  drawing  in  of  the  breath,  is  called  inspiration;  the  second,  or 


WHEN  ONE  BREATHES  OUT, 
THE  LUNGS  CONTRACT. 


WHEN  ONE  BREATHES  IN,  THE 
LUNGS  EXPAND. 


THE  BREATH  OF  LIFE 


in 


sending  out  of  the  breath,  is  called  expiration.  As  a  rule  the 
lungs  act  once  for  every  four  heart  beats.  See  how  long  you 
can  hold  your  breath.  It  is  not  ordinarily  possible  to  do  this 
for  more  than  half  a  minute,  but  if  you  will  first  take  several 
deep  inspirations,  you  will  find  that  you  can  hold  the  breath 
longer.  Why?  The  very  longest  time,  however,  that  the 
breath  can  be  held  even  by  the  most  practiced,  such  as  deep 
sea  divers,  is  three  minutes. 
In  natural  breathing,  when  the  movements  are  not  in  any 


WITH  PROPER  DRESSING  THE  LUNGS 
ARE  NOT  CROWDED,  AND  ALL  THE 
VITAL  ORGANS  HAVE  ROOM  TO  DO 
THEIR  PROPER  WORK. 


WITH  TOO  TIGHT  CLOTHING  THE  LUNGS 
ARE  NOT  ABLE  TO  EXPAND  PROP- 
ERLY, AND  ALL  THE  VITAL  ORGANS 
ARE  HANDICAPPED  IN  THEIR  WORK. 


way  interfered  with,  there  is  a  movement  of  the  whole  trunk, 
chiefly  in  the  region  of  the  waist.     There  are  two  very  How  to 
harmful  modes  of  breathing  which  must  be  avoided,  breathe 
One  of  these  is  called  costal  or  "rib"  breathing.    In  correctly 
it  the  movement  is  chiefly  in  the  upper  part  of  the  chest  and  the 
diaphragm  does  scarcely  any  work.     This  manner  of  breathing 


112  KEEPING  THE  BODY  IN  HEALTH 

is  common  among  some  women,  for  the  reason  that  they  con- 
strict the  body  with  tight  garments  and  so  interfere  with  the 
movements  of  the  diaphragm  and  the  lower  rib  muscles.  The 
work  of  the  diaphragm  assists  the  circulation  and  the  digestion 
as  well  as  the  breathing,  and  anything  that  interferes  with  its 
action  is  injurious. 

Although  women  dress  much  more  healthfully  now  than  they 
did  even  a  few  years  ago,  this  manner  of  breathing  is  still  com- 
mon among  them.  It  has  given  rise  to  the  idea  that  women 
naturally  breathe  in  a  different  way  from  men;  that  is,  only 
with  the  upper  part  of  the  chest.  This  idea  is  shown  to  be 
incorrect  by  the  fact  that  little  girls  and  uncivilized  women 
breathe  in  exactly  the  same  way  that  boys  and  men  do ;  that  is, 
by  an  expansion  of  the  whole  chest,  particularly  of  the  lower 
part. 

Another  unnatural  method  of  breathing  is  called  "  abdominal 
breathing."  It  is  caused  by  weakness  of  the  muscles  of  the 
abdomen  and  is  most  common  among  men  who  lead  sedentary 
lives.  The  weakened  muscles  yield  to  the  downward  pressure 
of  the  diaphragm,  and  the  abdomen  bulges  forward.  There 
is  very  little  movement  of  the  rib  muscles.  The  diaphragm 
does  all  the  work,  and  the  upper  thorax  does  not  expand  at 
all.  The  proper  ventilation  of  the  lungs  does  not  take  place, 
and  the  abdomen  becomes  prominent. 

Neither  costal  nor  abdominal  breathing  brings  the  lungs 
fully  into  action.  In  those  parts  that  remain  idle,  the  air  stag- 
nates, and  carbon  dioxide  and  other  poisons  accumulate.  The 
germs  of  pneumonia  and  tuberculosis  and  other  disease-producing 
microbes  are  likely  to  find  lodgment  in  these  idle  parts. 

The  muscles  of  the  abdomen  are  of  assistance  to  us  in  breath- 
ing. As  the  breath  is  drawn  in  when  the  chest  is  fully  expanded, 
the  abdominal  muscles  are  stretched  and  made  tense,  because 


THE  BREATH  OF  LIFE 


THE  PICTURE  SHOWS  ONE  WAY  TO  KEEP  THE  ABDO- 
MINAL MUSCLES  IN  GOOD  CONDITION  THROUGH 
EXERCISE.  STRONG  ABDOMINAL  MUSCLES  ASSIST 
IN  BREATHING. 


of  the  pressure  of  the  diaphragm  upon  the  organs  contained  in 
the  abdomen.  In  expiration,  these  muscles  contract,  as  does 
rubber  released  after  stretching ;  and  by  pushing  the  abdominal 
organs  upward  again,  they 
aid  in  crowding  the  air 
out  of  the  lungs,  and  in 
preparing  for  another  in- 
coming breath.  In  order 
to  serve  this  useful  pur- 
pose, the  abdominal  mus- 
cles must,  of  course,  be 
kept  vigorous  by  exercise. 

The  proper  passage  for  the  air  into  the  lungs  is  through  the 
nostrils,  which  are  especially  fitted  for  purifying  and  warming 
it.  The  nostrils  are  guarded  by  hairs  which  strain  out  dust, 

and  their  mucus  also  catches 
dust  and  germs.  The  nose  not 
only  acts  as  a  strainer,  but  it 
also  warms  the  air,  moistens  it 
when  it  is  too  dry,  and  warns 
us  when  it  is  impure. 

Many  persons  acquire  the 
harmful  habit  of  breathing 
through  the  mouth.  Mouth 
breathing  in  children  is  usually 
caused  by  adenoids,  a  growth 
of  tissue  which  often  nearly  fills 
the  breathing  passages.  You 
know  how  uncomfortable,  how 
stuffy  and  stupid  you  feel  when 

ADENOIDS  OBSTRUCT   BREATHING  AND  MAKE    the     nasal     passages     are     ob- 

ONE     UNCOMFORTABLE    AND     EVEN    STUPID. 

THEY  SHOULD  ALWAYS  BE  REMOVED.  StrUCted  by  means   of   a       Cold 


KEEPING  THE  BODY  IN  HEALTH 


in  the  head."  The  boy  or  girl  who  has  adenoids  is  always  in  this 
condition.  As  a  result  of  the  obstruction  of  the  air  passages,  the 
whole  body  suffers  from  lack  of  oxygen.  The  mouth  breather 
can  usually  be  distinguished  by  his  peculiar  expression  and  half- 
dazed  condition.  He  is  inattentive  and  cannot  understand  or 
study  well.  His  eyes  are  usually  dull,  his  expression  stupid,  and 
the  open  mouth,  which  is  necessary  for  the  passage  of  air,  adds 


THIS  BOY'S  MOUTH  BREATHING  WAS 

CAUSED  BY  ADENOIDS. 


THE  SAME  BOY  AFTER  THE  ADENOIDS 
WERE  REMOVED.  IT  IS  EASY  FOR 
A  SURGEON  TO  REMOVE  THEM. 


to  the  unattractiveness  of  his  appearance.  Sometimes  as  a  re- 
sult of  mouth  breathing  the  features  become  distorted,  the  upper 
lip  becomes  shortened,  and  the  upper  teeth  project.  Adenoids 
are  frequently  a  cause  of  deafness.  A  physician  should  always 
be  consulted  when  mouth  breathing  is  found  to  be  a  habit.  The 
removal  of  the  adenoids  is  a  very  simple  matter,  but  their  effects 
if  allowed  to  remain  are  serious  and  may  affect  a  person's  health 
for  the  rest  of  his  life. 
-  "To  breathe  well  is  to  live  well,  —  to  live  longer  and  better.' * 


THE  BREATH  OF  LIFE  115 

While  the  lungs  are  to  some  extent  under  our  control,  still 
their  action  is,  like  that  of  the  heart,  automatic,  or  self -regulating. 
During  sleep  as  well  as  during  waking  hours,  their  movements 
are  carried  on  with  rhythmical  regularity.  The  breathing  is 
not  so  deep  during  sleep  as  during  activity.  It  is  also  slower. 
Less  oxygen  is  used  when  the  body  is  asleep,  and  this  results  in 
lessened  breathing.  The  work  of  the  liver  and  the  kidneys  and 
the  repairing  work  of  the  cells  goes  on  during  sleep,  and  this 
requires  oxygen.  Hence  the  body  should  be  supplied  with  an 
abundance  of  fresh  air  during  sleep  by  proper  ventilation  of  the 
sleeping  room.  The  amount  of  air  taken  in  during  sleep  may  be 
increased  by  enlarging  the  capacity  of  the  lungs  by  suitable 
exercise  while  one  is  awake.  It  was  found  by  experiment  that 
the  amount  of  air  taken  into  the  lungs  during  sleep  was  doubled 
in  students  whose  breathing  capacity  had  been  increased  by 
exercise. 

The  act  of  breathing  is  a  blood-pumping  process,  as  well  as 
being  the  means  by  which  air  is  moved  in  and  out  of  the  lungs. 
The  enlarging  of  the  thorax,  by  means  of  which  air  is  How 
sucked  into  the  lungs,  helps  at  the  same  time  to  suck  breathing 
the  blood  in  toward  the  great  veins  that  lead  to  the  circulation 
heart.    While  this  is  happening,  the  downward  pressure  and 
of  the  diaphragm,  which  presses  the  abdominal  organs  digestion 
against  the  muscular  walls  of  the  abdomen,  serves  to  force  the 
blood   upward.     This   empties    the   blood  of  the  veins   in  the 
abdominal  cavity  into  the  chest,  thus  helping  it    on    toward 
the  heart.     You  can  see  from  this  that  deep  breathing  aids  the 
circulation  of  the  blood. 

The  stomach  lies  just  below  the  diaphragm,  which,  as  it 
moves  up  and  down,  kneads  the  stomach  and  its  contents  and 
in  this  way  assists  the  work  of  mingling  the  foods  and  the  digestive 
fluids.  In  the  ordinary  breathing  of  a  person  who  takes  little 


Ii6  KEEPING  THE  BODY  IN  HEALTH 

active  exercise,  the  movements  of  the  chest  are  slight,  and  the 
action  of  the  diaphragm  produces  small  effect ;  but  by  moderate 
exercise  the  movements  are  more  than  doubled,  and  the  stomach 
is  then  kneaded  in  a  vigorous  manner.  In  this  way  moderate 
exercise  after  eating  is  beneficial,  though  violent  exercise  should 
be  avoided.  Why?  Would  the  practice  of  taking  breathing 
exercises  after  meals  be  helpful  to  digestion  ?  Why  ? 

The  use  of  alcohol  or  tobacco  is,  as  you  might  expect,  in- 
jurious to  the  respiratory  passages  and  the  lungs.  You  know 
Effects  of  t^iat  alc°h°l  greatly  weakens  the  power  of  the  body  to 
alcohol  resist  germs.  One  who  uses  alcohol  is  therefore  espe- 
and  cially  liable  to  attacks  of  grippe  and  pneumonia,  as 

tobacco  on  well  as  to  catarrh  of  the  a{r  passages.  The  smoke  of 
the  lungs 

cigarettes    contains    a   poisonous   gas    called   carbon 

monoxide.  When  .this  smoke  is  inhaled,  as  it  frequently  is  by 
smokers,  both  the  poisonous  gas  and  the  tobacco  poison  get  into 
the  blood  in  the  lung  capillaries  and  are  a  source  of  injury  to  the 
cells. 

Dr.  Webb,  who  examined  many  thousands  of  soldiers  during 
the  World  War,  found  that  practically  all  smokers  show  evi- 
dence of  congestion  and  irritation  of  the  lungs.  The  records  of 
the  Phipps  Institute,  of  Philadelphia,  show  that  non-smokers 
suffering  from  tuberculosis  are  more  likely  to  recover  from  the 
disease  than  smokers.  In  some  parts  of  the  United  States, 
tuberculosis  is  increasing  among  men,  while  it  is  decreasing 
among  women.  It  is  quite  possible  that  one  reason  for  this  is 
the  rapid  increase  within  the  last  few  years  of  the  smoking 
habit  among  men.  If  the  habit  of  smoking  increases  among 
women,  the  difference  just  mentioned  may  grow  less. 

Nothing  is  of  more  importance  for  a  long  and  vigorous  life 
than  large  lung  capacity.  By  means  of  an  instrument  called 
the  spirometer,  into  which  a  person  breathes  after  taking  a  deep 


THE  BREATH  OF  LIFE 


117 


inspiration,  it  is  possible  to  find  out  the  vital  capacity,  that  is, 
the  amount  of  air  change  which  takes  place  in  the  lungs.     A 
person's  lung  strength  can  be  learned,  however,  with-  Developing 
out  the  use  of  the  spirometer,  by  testing  the  ability  to  lung 
endure  exercise  which  taxes  breathing  power,  such  as  caPacity 
running  up  and  down  stairs  or  other  running  exercises.     Ex- 
treme  breathlessness    caused   by   moderate    exercise   indicates 
either  that  the  heart  is  weak 
or   that   the   breathing  ca- 
pacity needs  developing. 

Any  exercise  which  com- 
pels full,  deep  breathing  is  a 
valuable  means  of  devel- 
oping the  lung  capacity. 
Breathing  power  depends 
upon  the  strength  of  the 
muscles  that  control  the 
chest  walls,  as  well  as  upon 
the  size  of  the  chest.  Ex- 
ercise in  a  gymnasium, 
chopping  and  sawing  wood, 
digging,  laundry  work, 
scrubbing,  and  all  sorts  of 
active  housework  and  farm 
work  are  good  for  develop- 
ing the  chest. 

When     a    chest    is    not 

stretched  to  its  fullest  capacity  many  times  daily,  it  is  likely  to 
lose  its  capacity  for  holding  much  air,  especially  after  the  age  of 
thirty.  The  proper  time  for  chest  development  is  in  childhood 
and  youth.  During  this  period  the  soundness  of  the  heart 
makes  it  possible  to  take  without  injury  those  vigorous  exercises 


THE  SPIROMETER  MEASURES  THE  CAPACITY  OF 
THE  LUNGS.  YOU  SHOULD  TEST  YOUR  LUNGS 
AND  SEE  IF  YOU  CAN  INCREASE  YOUR  CA- 
PACITY. 


Ii8  KEEPING  THE  BODY  IN  HEALTH 

which   are  necessary  to  secure    the    highest    degree    of    lung 
capacity. 

We  have  seen  that  the  breathing  movements  are  for  the  pur- 
pose of  supplying  the  cells  with  oxygen.  The  breathing  is 
therefore  regulated  according  to  the  needs  of  the  cells.  When 
the  large  muscles  of  the  body  are  actively  at  work,  as  in  running, 
oxygen  is  rapidly  used  up  by  the  working  cells,  and  the  blood  is 
filled  with  carbon  dioxide.  The  heart  beats  more  rapidly  to 
send  the  impure  blood  to  the  lungs  for  purification  and  a  supply 


LIVELY  GAMES  OF  ANY  SORT  THAT  ONE  ENJOYS  WILL  INCREASE  THE  CAPACITY  OF  THE  LUNGS. 

of  oxygen.  In  this  way  a  sort  of  thirst  for  air  is  created  and 
deep  and  rapid  breathing  is  the  result.  Exercises  of  this  sort 
are  far  superior  to  so-called  " breathing  exercises/'  in  which 
the  lungs  are  forcibly  compelled  to  take  in  more  than  the  or- 
dinary amount  of  air,  though  these  latter  exercises  have  some 
value.  The  impulse  which  comes  from  within,  from  the  so- 
called  "respiratory  centers/'  stimulates  the  respiratory  muscles 


THE  BREATH  OF  LIFE  119 

so  that  they  cause  the  chest  to  execute  the  strongest  breathing 
movements  with  the  greatest  ease,  ventilating  every  portion 
of  the  lungs  and  filling  every  air  cell  to  the  utmost  capacity. 

Running,  or  other  active  exercise  of  the  leg  muscles,  is  an 
excellent  means  of  increasing  the  lung  capacity.  At  first  the 
breathing  is  slightly  difficult,  but  after  a  short  time,  Increasing 
when  the  runner  has  his  " second  wind,"  respiration  luns 
becomes  easier.  The  entire  lung  surface  is  then  capaci  y 
brought  into  action.  In  ordinary  breathing  not  all  the  lung 
surface  is  used ;  hence  the  lungs  are  likely  to  become  diseased, 
unless  brought  into  full  use  by  exercises  which  necessitate  deep 
and  full  respiration.  Runners  always  have  large  and  active 
chests,  and  sedentary  persons  usually  have  chests  of  limited 
capacity  with  rigid  walls. 

One  of  the  best  exercises  for  developing  the  breathing  powers 
is  swimming.  The  position  of  the  body  and  the  active  move- 
ments of  the  arms  and  legs  make  swimming  a  most  effective 
breathing  exercise.  The  contact  of  the  skin  with  the  cold  water 
also  stimulates  the  movements  of  the  chest,  while,  by  increasing 
the  energy  of  the  muscles  it  encourages  vigorous  muscular  move- 
ments. Even  the  ordinary  cold  bath  is  an  excellent  means 
of  enlarging  respiration.  It  deepens  the  breathing,  and  this 
in  time  results  in  greater  lung  capacity.  It  also  increases  the 
circulation  of  the  blood  in  the  lungs,  which  means  greater  ab- 
sorption of  oxygen.  The  daily  cold  bath,  by  increasing  the  re- 
sistance of  the  body,  prevents  colds  and  other  more  serious  dis- 
eases of  the  lungs  and  respiratory  passage.  In  experiments 
made  with  young  people,  the  girth  or  size  of  the  chest  was  in- 
creased in  some  cases  one  and  one  half  inches  in  a  few  weeks 
as  a  result  of  swimming  exercises. 

We  need  a  large  amount  of  air  —  a  pint  of  air  at  every  breath. 
If  we  can  take  more,  all  the  better.  A  consumptive  often  does 


120  KEEPING  THE  BODY  IN  HEALTH 

not  take  half  this  amount.  A  pint  at  every  breath,  sixteen 
breaths  a  minute,  equals  two  gallons  every  minute ;  that 
amounts  to  120  gallons  an  hour,  almost  3000  gallons  a  day. 
Three  thousand  gallons  would  be  how  many  barrels  ?  —  Nearly 
100  barrels  of  air.  But  these  figures  do  not  indicate  the 
amount  of  air  required  to  insure  the  purity  of  the  air  we 
breathe.  A  pint  of  air  which  is  breathed  out  from  the  lungs 
affects  at  least  two  cubic  feet  of  air,  rendering  it  unfit  to  breathe. 
In  other  words,  for  every  pint  of  air  we  use  by  taking  it  into  our 
lungs,  we  spoil,  by  sending  out  a  pint  of  impure  air,  more  than  a 
hundred  times  as  much  air  or,  at  least  ten  thousand  barrels  of 
air  daily.  So  the  actual  daily  ration  of  air,  that  is,  the  amount 
of  fresh  air  each  person  requires,  is  about  forty  to  fifty  thousand 
cubic  feet,  or  ten  to  twelve  thousand  barrels  of  air. 

Special  breathing  exercises,  as  well  as  those  muscular  move- 
ments which  create  a  "  thirst  for  air,"  are  beneficial  because  they 
keep  the  chest  flexible  and  ventilate  the  lungs.  These  move- 
ments, as  was  mentioned  earlier,  also  exercise  a  beneficial  effect 
upon  the  digestive  organs  lying  below  the  diaphragm.  Every 
time  the  diaphragm  contracts  it  gives  them  a  hearty  squeeze, 
so  to  speak,  emptying  out  the  blood  contained  in  them,  as  one 
empties  a  moist  sponge  by  pressure  upon  it.  All  exercises 
which  increase  the  strength  of  the  abdominal  muscles  are  a 
means  of  aiding  and  improving  the  breathing. 

One  should  make  a  practice  of  breathing  deeply  for  a  few 
minutes  several  times  a  day.  This  should  of  course  be  done 
outdoors  where  the  air  is  pure.  A  convenient  time  is  on  the 
way  to  and  from  school.  Simply  filling  the  lungs  with  air  until 
every  part  is  expanded  and  then  slowly  exhaling  is  very  bene- 
ficial. Do  this  several  times  in  succession.  When  you  are  tired 
or  feel  dull  and  stupid,  try  the  effect  of  going  outdoors  or  opening 
a  window  and  taking  a  few  deep  breaths.  You  will  be  sur- 


THE  BREATH  OF  LIFE  121 

prised  to  see  how  this  will  rest  and  refresh  you  and  quicken  the 
activity  of  your  brain.  After  being  shut  up  in  a  close  room  or 
in  an  ill-ventilated  hall  or  church,  be  sure  to  ventilate  the  lungs 
thoroughly  by  taking  a  few  deep-breathing  exercises  in  the 
outdoor  air.  Weariness,  dullness,  and  nervousness  are  usually 
overcome  by  the  increased  ventilation  of  the  body  secured 
by  deep  breathing. 

Care  should  be  taken  that  the  breathing  movements  are  in 
no  way  interfered  with  by  the  clothing.  Corsets  or  tight  belts 
are  likely  to  restrict  the  action  of  the  rib  muscles,  and  in  that 
way  they  tie  the  handles  of  nature's  bellows,  the  lungs. 

The  vocal  cords  are,  as  we  have  seen,  situated  in  the  larynx, 
at  the  entrance  to  the  windpipe.  " Adam's  apple"  will  show 
you  just  where  the  larynx  is  located.  Within  the  The 
larynx  are  two  bands  of  tissue  which  run  across  the  voice 
side  walls  from  the  front  to  the  back.  When  these  vocal  cords 
are  brought  together  and  air  is  forced  through  them,  sound  is 
produced.  Speech  is  produced  by  modifying  the  voice  by 
means  of  the  tongue,  teeth,  lips,  and  throat.  The  pitch  of 
the  voice  depends  upon  the  weight,  length,  and  tightness  of 
the  cords.  Change  of  pitch  is  brought  about  by  the  tighten- 
ing or  loosening  of  the  vocal  cords.  In  a  stringed  instrument, 
such  as  a  violin,  a  heavy  string  gives  a  lower  tone  than  a  light 
one.  In  strings  of  the  same  weight,  a  short  string  gives  a 
higher  tone  than  a  long  one,  and,  in  those  of  the  same  weight 
and  length,  a  tight  string  gives  a  higher  tone  than  a  loose  one. 
In  like  manner  when  the  vocal  cords  are  long  and  loosely 
stretched,  the  voice  is  low  in  pitch.  When  the  cords  are  short 
or  tightly  stretched,  the  pitch  is  high. 

A  grown  person  has  a  larger  larynx  and  hence  longer  vocal 
cords  than  a  child,  and  consequently  a  voice  of  lower  pitch.  The 
change  of  voice  in  a  boy  between  the  ages  of  fourteen  and 


122 


KEEPING  THE  BODY  IN  HEALTH 


eighteen  is  due  to  the  enlargement  of  the  larynx,  which  takes 
place  normally  at  that  period.  Do  you  think  the  voice  should 
be  given  severe  use  while  it  is  changing?  A  man  has  a  larger 
larynx  than  a  woman  and  hence  a  voice  of  lower  pitch.  When 


fyiglottis 


THE  LARYNX 

A  and  a,  the  vocal  cords  in  resting  position ;  B  and  b,  the  vocal  cords  in  position  for 

producing  -voice 

men  and  women  are  singing  together  the  voices  of  the  men  are 
an  octave  lower  than  those  of  the  women. 

An  important  means  of  preserving  the  voice  is  to  avoid  taking 
cold.  If  a  cold  has  been  taken,  the  voice  should  not  be  used 
in  singing  or  loud  speaking  until  the  hoarseness  is  relieved. 
Permanent  injury  to  the  voice  sometimes  results  from  disregard- 
ing this  rule.  The  use  of  rich  foods  and  irritating  condiments 
injures  the  voice  by  producing  a  congestion  or  chronic  inflam- 
mation of  the  throat.  Smokers  are  especially  liable  to  disease 
of  the  throat  because  the  hot,  irritating  smoke  is  brought  into 
contact  with  the  delicate  vocal  cords. 

In  speaking,  and  especially  in  singing,  the  muscles  of  the 
waist  should  be  used.  Increased  force  as  well  as  greater  volume 


THE  BREATH  OF  LIFE  123 

may  be  given  to  the  voice  by  the  use  of  the  muscles  about  the 
diaphragm,  and  the  voice  will  then  be  much  less  easily  fatigued. 
A  high  pitched,  strained  voice  should  be  avoided,  as  it  is  irri- 
tating to  the  throat,  tiring  to  the  speaker,  and  disagreeable  to 
the  hearer.  Those  who  have  not  learned  the  proper  use  of  the 
muscles  in  speaking  or  singing  are  very  likely  to  use  the  muscles 
of  the  throat  and  upper  part  of  the  chest  in  a  strained  injurious 
way  during  loud  speaking  and  singing. 

HEALTH  PROBLEMS 

1.  Tell  what  happens  to  a  breath  of  air,  from  the  start  until  it  comes 
out  of  the  body.    Tell  the  things  that  it  does  in  the  body,  and  the  changes 
that  come  to  it. 

2.  Have  you  ever  had  a  particle  of  food  go  down  your  "windpipe"  a 
little  way?     Describe  your  experience  when  this  happened. 

3.  What  arrangement  has  nature  provided  so  that  if  food  goes  the 
wrong  way  the  body  will  try  to  throw  it  out  ?     Will  the  body  do  this  with- 
out your  directing  it  ?     WThy  ? 

4.  Feel  your  lungs  when  you  are  breathing  deeply ;  tell  how  it  is  possible 
for  the  lungs  to  expand  and  to  contract.     Are  there  2000  square  feet  in  the 
floor  of  the  room  in  which  you  are  now?     Can  you  imagine  the  membrane 
in  the  lungs  as  covering  2000  square  feet  ? 

5.  Why  is  there  so  much  mucus  when  you  have  a  "cold"?    Why  does 
the  nose  run  freely  when  one  is  breathing  a  good  deal  of  dust  ? 

6.  See  if  you  can  bring  to  school  some  device  that  acts  like  a  piston. 
Show  the  class  that  air  is  sucked  in  when  the  piston  is  moved. 

7.  Explain  coughing;   how  does  it  differ  from  breathing?    What  is  a 
hiccough?    What  is  yawning?    What  is  sighing? 

8.  See  if  you  can  tell  with  what  part  of  your  lungs  you  habitually 
breathe.     If  you  try,  can  you  breathe  with  the  entire  lung  space? 

REVIEW  QUESTIONS 

1.  What  is  the  purpose  of  breatHing? 

2.  How  do  the  cells  far  in  the  interior  of  the  body  get  their  oxygen?  ' 

3.  What  is  meant  by  "division  of  labor"  among  the  cell  groups  in  the 
body? 


124  KEEPING  THE  BODY  IN  HEALTH 

4.  What  is  the  means  of  communication  between  the  lungs  and  the 
cells  throughout  the  body  ? 

5.  What  is  the  use  of  oxygen  in  the  body? 

6.  Describe  the  breathing  passages,  telling  about  the  parts  and  their 
uses. 

7.  What  is  meant  by  air  passages? 

8.  Where  are  the  tonsils  located?    What  are  their  uses?    What  may 
happen  when  they  become  swollen  and  diseased  ? 

9.  Why  do  people  sometimes  have  tonsils  removed? 

10.  What  arrangement  has  nature  provided  so  that  the  air  we  breathe 
goes  to  the  lungs  and  the  food  goes  down  the  esophagus  to  the  stomach? 

11.  With  what  are  the  breathing  passages  lined?    How  does  this  lining 
assist  in  keeping  good  health  ? 

12.  What  are  the  cilia,  and  what  do  they  do  to  help  the  body  keep  in 
good  health? 

13.  What  change  in  color  occurs  to  the  blood  as  it  passes  through  the 
lungs?    Through  the  capillaries? 

14.  Where  does  the  carbon  dioxide  come  from  which  escapes  from  the 
body  through  the  lungs  ? 

15.  What  is  the  color  of  the  blood  in  the  arteries ?     In  the  veins?    Ex- 
plain. 

16.  How  are  the  lungs  ventilated  ? 

17.  Describe  the  cavity  in  which  the  lungs  are  placed. 

18.  How  does  the  diaphragm  act  so  as  to  help  one  to  breathe? 

19.  What  is  the  meaning  of  inspiration?     Of  expiration? 

20.  Why  is  there  action  of  the  entire  lungs  when  one  breathes  correctly? 

2 1 .  What  causes  some  persons  to  breathe  through  the  mouth  ? 

22.  What  is  the  effect  of  mouth  breathing  upon  one's  health  and  mind? 

23.  What  should  be  done  for  one  whose  air  passages  are  filled  with 
adenoids?    Why? 

24.  How  does  breathing  assist  digestion? 

25.  Does  one  breathe  as  heavily  or  as  rapidly  during  sleep  as  when  he 
is  awake?    Why? 

26.  What  is  the  effect  of  alcohol  upon  the  lungs? 

27.  Why  is  it  desirable  to  have  large  lung  capacity? 

28.  Mention  ways  in  which  it  is  possible  to  enlarge  the  lung  capacity. 
What  is  the  value  of  running,  swimming,  and  daily  cold  bath,  in  developing 
lung  capacity? 


THE  BREATH  OF  LIFE  125 

29.  Suppose  one  does  not  stretch  his  lungs  to  their  full  capacity  very 
frequently,  what  may  happen  to  them  ? 

30.  Where  are  the  vocal  cords  located?    Describe  them. 

31.  What  is  the  difference  between  the  vocal  cords  of  a  grown  person 
and  those  of  a  child  ? 

32.  How  is  it  possible  to  change  the  pitch  in  one's  voice? 

33.  What  may  happen  if  one  strains  the  voice  while  he  is  hoarse? 

34.  What  muscle  should  be  used  especially  in  speaking  and  singing? 


CHAPTER  IX 
How  THE  BODY  CLEANSES  ITSELF 

IN  any  community  of  people  there  is  a  certain  amount  of 
waste  matter  to  be  disposed  of.  In  a  well-regulated  city  the 
Organs  of  garbage  or  waste  is  daily  removed  from  the  houses, 
excretion  an(i  other  offensive  waste  matters  are  carried  away 
by  means  of  sewers.  If  wastes  are  not  promptly  removed,  the 
health  of  the  people  will  be  in  danger. 

We  have  found  that  the  cells  that  make  up  the  body  community 
not  only  take  in  food  and  oxygen,  but  also  send  out  waste 
matters  into  the  lymph  that  surrounds  them.  Of  course,  the 
health  of  the  cells  depends  upon  the  prompt  removal  of  these 
wastes.  The  work  of  sending  them  out  of  the  body  is  called 
excretion,  and  the  cell  groups  that  do  the  work  are  called  the 
organs  of  excretion  or  of  elimination. 

There  are  four  organs  by  means  of  which  waste  and  poisonous 
matters  are  removed  from  the  body.  Two  of  these  we  have 
already  considered.  They  are  the  intestine,  which  removes  the 
indigestible  and  unused  residues  of  the  food  together  with  such 
bile,  refuse  lime,  and  iron  as  the  body  rejects;  and  the  lungs, 
which  carry  off  the  carbon  dioxide.  The  other  two  organs  are 
the  kidneys  and  the  skin. 

When  fuel  is  burned  in  a  stove,  the  greater  part  of  it  passes 
off  up  the  chimney  in  the  form  of  gas  and  smoke,  but  a  small 
portion  remains  in  the  form  of  ashes.  The  same  thing  takes 
place  when  food  is  burned  in  the  body.  When  fats  and  carbo- 
hydrates are  burned  in  the  body,  they  are  changed  into  gaseous 

126 


HOW  THE  BODY  CLEANSES  ITSELF 


127 


Artery. 


Descending 
Aorta 


Asccnc/i'nj 
Vena  Cava 


Uretet 


poison  (carbon  dioxide)  and  water.  The  gaseous  poison  escapes 
through  the  lungs,  which  are  the  chimney  of  the  body,  and  each 
of  the  organs  of  excretion  carries  off  some  of  the  water.  Water 
is  constantly  being  given  off  from  the  lungs  and  the  skin.  The 
moisture  in  the  breath  may  be 
seen  out  of  doors  on  a  cold  day ; 
and  when  the  body  is  over- 
heated the  perspiration  becomes 
visible  upon  the  skin.  A  cer- 
tain amount  of  water  is  also  dis- 
charged through  the  intestine. 
The  kidneys  are,  however,  the 
chief  means  of  removing  any 
excess  water  from  the  blood. 

The  combustion  of  proteid 
foods  produces,  besides  carbon 
dioxide  and  water,  a  certain 
amount  of  wastes,  which  corre- 
spond to  the  ashes  that  would 
be  left  behind  if  the  food  were 
burned  in  a  stove.  These 
wastes,  after  being  prepared  and 
made  soluble,  are  extracted 
from  the  blood  and  sent  out  of 
the  body  by  the  kidneys.  A 
small  amount  both  of  the  gaseous  poison  and  of  other  wastes 
passes  out  through  the  skin  in  the  perspiration. 

The  kidneys,  which  are  very  important  organs  of  excretion, 
are  located  at  the  back  part  of  the  abdominal  cavity,  just  below 
the  lower  ribs.  They  are  placed  close  to  the  spinal  column, 
one  on  each  side.  Each  kidney  is  a  gland  shaped  like  a  kidney 
bean,  and  weighs  from  four  to  six  ounces. 


THE  KIDNEYS  PERFORM  A  VERY  NECESSARY 
WORK  IN  REMOVING  POISONOUS  WASTES 
FROM  THE  BODY.  IF  ONE'S  KIDNEYS 
SHOULD  CEASE  WORKING,  HE  COULD 
NOT  LIVE  LONG. 


128 


KEEPING  THE  BODY  IN  HEALTH 


Examined  under  the  microscope,  the  substance  of  the  kidney 
is  found  to  be  made  up  of  very  delicate  tubes,  which  begin  near 
the  surface  of  the  organ  in  little  round  sacs.  Each  sac  contains 
a  minute  coiled  blood  vessel.  The  tubes  leading  from  the  sacs 
combine  as  they  pass  towards  the  center,  becoming  larger  in 
size,  and  finally  opening  into  a  cavity  in  the  kidney.  This 
cavity  communicates  with  a  long  tube  which  passes  to  the 
bladder. 

Each  kidney  contains  about  2,000,000  cells.  The  length  of 
each  tubule  is  about  one  inch,  making  an  aggregate  of  more  than 

sixty  miles  of  tubing  for  both  kid- 
neys. Each  of  these  little  sacs, 
or  kidney  cells,  produces  during 
a  lifetime  of  sixty  years  about 
two  teaspoonfuls  of  fluid,  or 
one  drop  every  three  months. 
This  statement  will  give  some- 
thing of  an  idea  of  the  extreme 
delicacy  of  the  structure  of  the 
kidneys  and  of  the  necessity  for 
taking  the  greatest  care  of  these 
fragile  organs.  The  kidney  ex- 
cretion contains  some  of  the 
DELICATE  WAY  AND  ARE  EASILY  INJURED,  most  poisonous  waste  elements 

OVEREATING,     ESPECIALLY  OF    PROTEIN        ,.    .,        -,       ,  TTT1  ,. 

FOODS,  INCREASES  THE  WORK  OF  THE    of  the  body.     When  from  any 

cause  the  action  of  the  kidneys 
ceases,  death  soon  takes  place. 
The  kidneys  are  always  at  work,  but  are  more  active  at  some 
times  than  at  others.  Anything  that  increases  the  flow  of  blood 
through  the  kidneys  stimulates  them  to  greater  activity.  Drink- 
ing water  freely  is  beneficial  to  the  kidneys.  Water  dissolves 
the  poisons  of  the  tissues  and  aids  the  kidneys  in  removing  them. 


Pe/v/s 


Pyramid 


Ureter 


THE  KIDNEYS  ARE  CONSTRUCTED  IN  A  VERY 


KIDNEYS  AND  IS 
THEM. 


LIKELY  TO  OVERTAX 


HOW  THE  BODY  CLEANSES  ITSELF  129 

In  summer,  especially,  when  a  large  amount  of  water  passes  off 
through  the  skin  in  the  perspiration,  it  is  very  necessary  to 
drink  a  sufficient  amount  of  water  to  make  good  the  loss  from 
this  source. 

Overeating,  especially  of  protein  foods,  the  waste  products 
of  which  it  is  the  business  of  the  kidneys  to  remove,  increases 
the  work  of  the  kidneys,  and  is  likely  to  overtax  them.  Habits  and 
The  kidneys  are  in  close  sympathy  with  the  skin,  foods  that 
Both  remove  water  and  wastes  from  the  blood.    What-  injure  the 
ever  interferes  with  the  work  of  the  one  will  impose 
extra  labor  upon  the  other.     Sedentary  habits,  neglect  of  bath- 
ing, exposure  to  severe  cold,  failure  to  eliminate  waste  matters 
regularly  from  the  colon,  the  use  of  alcohol,  tobacco,  tea,  coffee, 
and  patent  medicines,  and  the  excessive  use  of  meat  may  be 
mentioned  as  the  chief  causes  of  kidney  diseases,  which  are 
rapidly  increasing  in  our  country. 

Alcohol  injures  the  kidneys,  as  it  does  the  liver  and  all  other 
parts  of  the  body  with  which  it  comes  in  direct  contact.  It 
causes  inflammations  and  changes  which  finally  result  in  the 
disease  and  decay  of  the  organs.  Disease  of  the  kidneys  is  very 
frequent  among  beer  drinkers. 

The  liver,  as  we  have  seen,  completes  the  work  of  digestion. 
When  it  becomes  disabled  by  the  use  of  alcohol  or  in  other 
ways,  some  portions  of  the  food  are  allowed  to  pass  into  the 
general  circulation  without  having  been  so  changed  by  the 
liver  that  they  'can  be  used  by  the  cells  in  building  up  the 
body.  The  removal  of  these  useless  substances  adds  greatly 
to  the  work  of  the  kidneys. 

We  see,  then,  what  a  chain  of  mischief  may  be  started  by  the 
use  of  alcohol. 

Before  studying  the  skin  in  its  work  of  cleansing  the  body,  we 
must  first  mention  its  other  uses  and  notice  how  it  is  constructed. 


130 


KEEPING  THE  BODY  IN  HEALTH 


The  chief  purposes  of  the  skin  are  (i)  to  form  a  protective 
covering  for  the  body,  in  order  to  prevent  the  entrance  of  harm- 
The  work  ful  substances  such  as  germs ;  (2)  to  regulate  the 
of  the  skin  heat  of  the  body,  keeping  it  at  a  constant  tempera- 
ture ;  (3)  to  receive  impressions  of  heat,  cold,  pain,  and  so  on ; 
(4)  to  a  small  extent,  as  we  have  seen,  to  assist  the  lungs  and 
the  kidneys  in  the  work  of  excretion. 

You  may  remember  that  the  outer  layer  of  the  skin  is  called 
the  epidermis.  This  is  a  covering  for  the  dermis,  which  contains 


/fe/r 


Sweat 


Fat  Ce/te 


Rootofffa/r  — 


—Sfa/r  FoMc/e 


ONE  CAN  HARDLY  BELIEVE  THAT  HIS  SKIN  IS  SO  REMARKABLY  CONSTRUCTED  AS  THIS  PICTURE 

INDICATES. 

the  active  parts  of  the  skin,  —  the  glands,  nerves,  and  blood 
vessels,  —  by  means  of  which  the  various  kinds  of  work  of  the 
skin  are  carried  on. 

The  flattened  cells  which  compose  the  outer  layers  of  the 
epidermis  are  all  the  time  drying  and  scaling  off,  and  for  that 
reason  the  skin  needs  to  be  constantly  renewed  by  the  making  of 
new  cells.  We  have  learned  that  cells  multiply  by  each  cell's 
dividing  into  two  new  cells.  The  cells  in  the  lower  layers 
of  the  epidermis  divide  in  this  way  and  form  new  cells  to  take  the 
place  of  those  that  have  been  thrown  off. 


HOW  THE  BODY  CLEANSES  ITSELF 


Since  the  epidermis  has  for  its  purpose  the  protection  of  the 
delicate  parts  beneath,  it  is  thickest  in  those  regions  of  the 
body  where  there  is  the  most  pressure.  On  the  soles  of  the  feet 
and  the  palms  of  the  hands  there  may  be  as  many  as  one  hundred 
layers  of  epidermal  cells,  while  on  other  parts  of  the  body  there 
are  not  more  than  twenty.  Constant  pressure  upon  any  part 
of  the  skin  causes  a  great  increase  in  the  number  of  epidermal 
cells  at  that  point.  A  corn  on  the  foot  is  due  to  the  thickening 
of  the  epidermis  resulting  from  the  pressure  of  the  shoe. 

The  hair  and  nails  are  curious  horny  structures  which  grow 
out  from  the  skin.  Hairs  are  found  upon  all  parts  of  the  body, 
with  the  exception  of  the  palms  of  the  hands  and  the  soles  of 
the  feet.  Each  hair  grows  from  a  small,  deep  pocket  in  the  skin, 
called  the  hair  follicle.  Both  nails  and  hair  are  constantly  being 
formed  in  the  dermis  and  pushed  upward.  The  uses  of  the 
hair  seem  to  be  to  protect  the  parts  beneath  from  changes  of  tem- 
perature, as  in  the  case  of  the  head,  and  to  protect  sensitive  parts 
from  dust  and  other  harmful  substances, 
as  in  the  eyelashes  and  eyebrows,  and 
the  hairs  of  the  nostrils. 

Opening  into  each  hair  follicle  are  one 
or  more  sebaceous  glands  which  pour  out 
an  oily  substance  to  moisten  the  hair, 
and  to  lubricate  the  skin  and  thus  pro- 
tect it  from  drying  and  chapping.  The 
color  of  the  hair  is  due  to  pigmented  cells 
like  those  which  give  the  skin  its  color. 

The  nails  grow  from  little  folds  in  the 
skin  and  from  the  tissues  over  which 
they  lie.  They  protect  the  ends  of  the 

fingers  and  toes,  increase  the  delicacy  of  the  sense  of  touch,  and 
aid  the  fingers  in  picking  up  small  objects. 


Body 


THE  FINGER  NAIL  GROWS  FROM  A 
LITTLE  FOLD  IN  THE  SKIN  AND 
FROM  THE  TISSUES  OVER 
WHICH  IT  LIES. 


132  KEEPING  THE  BODY  IN  HEALTH 

The  inner  layer  of  the  skin,  the  true  skin  or  dermis,  contains 
many  blood  vessels,  glands,  and  nerves,  and  also  minute  mus- 
cles connected  with  the  hairs.  When  one  is  chilly  these  muscles 
sometimes  contract,  causing  a  rough  appearance  of  the  skin 
commonly  called  "goose  flesh." 

The  outer  surface  of  the  true  skin  is  not  flat,  but  is  thrown  up 
into  moundlike  projections  called  papilla,  which  project  up  into 
the  epidermis.  Some  of  the  papillae  contain  blood  vessels  and 
nerve  endings.  The  large  number  of  blood  vessels  with  which  it 
is  provided  give  the  skin  such  vitality  that  small  wounds  in  it 
will  heal  very  rapidly,  if  the  blood  is  healthy.  Even  when  quite 
a  large  surface  of  the  skin  is  removed,  new  skin  will  grow  out 
from  the  edges  until  the  gap  is  entirely  covered. 

Since  it  is  the  protective  covering  of  the  body,  it  is  very 
important  that  the  skin  should  be  kept  from  injury.  Even  a 
slight  scratch  may  open  up  a  way  for  a  deadly  germ,  which  may 
cause  serious  and  even  fatal  results.  Wounds  in  the  skin  should 
be  cleansed  with  a  disinfecting  fluid  and  kept  covered. 

The  work  of  the  sweat  glands,  of  which  there  are  in  the  skin 
not  less  than  two  and  one  half  millions,  is  to  cool  the  body  by 
pouring  out  water  upon  the  skin.  This  they  are  doing  con- 
stantly, but  the  amount  of  water  is  usually  too  small  to  be  notice- 
able. When  it  evaporates  before  it  becomes  visible,  it  is  called 
insensible  perspiration.  The  amount  of  insensible  perspiration 
produced  daily  by  the  entire  skin  is  usually  from  one  and  one 
half  to  four  pints.  It  is  by  the  evaporation  of  the  perspiration 
that  the  body  is  cooled.  Exercise  or  heat  greatly  increases 
the  amount  of  perspiration,  so  that  it  becomes  visible  upon  the 
skin  and  is  known  as  sensible  perspiration. 

Perspiration  is  not  simply  a  heat-regulating  secretion.  It  is 
a  means  by  which  some  of  the  waste  matters  contained  in  the 
blood  are  carried  out  of  the  body.  When  the  water  evaporates 


HOW  THE  BODY  CLEANSES  ITSELF  133 

from  the  surface  of  the  body,  the  waste  matter  it  contained 
remains  on  the  skin  and  becomes  mixed  with  oil  from  the  se- 
baceous glands,  with  dead  epidermis,  and  with  dust  from  the 
air  and  the  clothing.  If  this  waste  is  not  regularly  removed  by 
bathing  and  friction  of  the  skin,  it  will  form  a  thin  coating  all 
over  the  body,  and  will  give  off  a  bad  odor  and  interfere  with 
the  work  of  the  skin.  Where  there  is  dirt,  there  are  germs. 
An  unclean  condition  of  the  skin  encourages  the  growth  of  germs 
upon  it,  and  some  of  them  may  get  down  into  the  hair  follicles 
and  the  sebaceous  glands,  and  cause  pimples  and  other  skin 
eruptions. 

HEALTH  PROBLEMS 

1.  Suppose  any  group  of  persons  in  your  community  who  remove 
wastes,  such  as  garbage  men,  should  cease  to  do  their  work,  what  would 
happen?    Have  you  ever  known  of  such  a  case? 

2.  Show  that  the  burning  of  food  in  the  body  leaves  something  like  the 
ashes  left  from  the  burning  of  wood  in  a  stove.     Suppose  the  ashes  in  a 
stove  or  a  furnace  should  not  be  removed  at  all.     What  would  happen, 
in  time,  to  the  fire?      Is  it  the   same   in   the   body   if   wastes   are  not 
removed  ? 

3.  Do  you  know  whether  persons  who  eat  a  great  deal  of  meat  and 
live  a  sedentary  life  are  inclined  to  be  troubled  with  kidney  diseases  ?    Ask 
your  physician  this  question.     If  he  tells  you  that  such  persons  are  likely 
to  have  kidney  diseases,  ask  him  why  and  remember  what  he  says. 

4.  Suppose  a  person  who  lives  indoors  should  eat  three  meals  a  day 
composed  largely  of  beans,  cheese,  lean  meat,  milk,  and  eggs.     Should  you 
expect  such  a  person  to  be  well  ?    Explain. 

5.  Suppose  the  liver  and  the  kidneys  could  speak  when  a  man  was 
about  to  take  a  glass  of  whisky,  what  do  you  think  they  would  say,  and 
why? 

6.  Suppose  you  should  cover  the  surface  of  your  body  with  wax,  what 
do  you  think  would  happen?     Would  the  case  be  about  the  same  if  you 
should  let  the  body  become  covered  with  the  wastes  thrown  out  by  the 
skin? 


134  KEEPING  THE  BODY  IN  HEALTH 

7.  Why  does  a  part  of  the  outer  skin  of  the  feet  rub  off  so  easily  after 
a  hot  foot  bath  ?    Why  is  there  so  much  of  this  skin  on  the  feet  ? 

8.  Show  in  some  way  that  the  sebaceous  glands  contain  an  oil  which 
they  pour  out  to  keep  the  skin  from  becoming  hard  and  dry. 

9.  Try  to  find  out  why  people  who  live  in  countries  where  there  is  a 
great  deal  of  sunshine  have  black  hair,  while  those  who  live  in  countries 
where  there  is  not  so  much  sunshine  have  lighter- colored  hair. 

10.   Think  of  some  way  to  show  that  there  is  invisible  perspiration  pour- 
ing out  from  the  skin  all  the  time. 

REVIEW  QUESTIONS 

1.  What  name  is  given  to  the  work  of  sending  wastes  out  of  the  body? 
To  the  organs  which  have  charge  of  getting  rid  of  wastes  ? 

2.  What  waste  products  are  formed  by  the  burning  of  food  in  the  body? 

3.  How  is  the  gaseous  poison,  carbon  dioxide,  removed  from  the  body? 

4.  What  waste  is  expelled  from  the  body  through  the  skin?    What 
through  the  kidneys? 

5.  Where  are  the  kidneys  located?     What  is  their  shape? 

6.  Describe  what  one  sees  when  he  looks  at  the  structure  of  the  kidneys 
through  a  microscope. 

7.  What  happens  when  the  kidneys  cease  to  do  their  work? 

8.  Why  is  it  desirable  to  drink  plenty  of  pure  water  ? 

9.  Suppose  the  skin  refused  to  do  its  work,  what  would  be  the  effect  on 
the  kidneys?    Why? 

10.  What  effect  do  the  following  practices  have  upon  the  kidneys :  over- 
eating (especially   of  protein  foods) ;  neglect  of  bathing ;  sedentary  habits ; 
the  using  of  alcohol  ? 

1 1 .  When  the  food  is  not  digested  properly,  do  the  kidneys  suffer  ?     Why  ? 

12.  Name  the  four  chief  purposes  of  the  skin. 

13.  What  is  the  outer  layer  of  skin  called,  and  what  is  its  use?     What 
is  the  inner  layer  of  skin  called,  and  what  is  its  use  ? 

14.  What  happens  to  the  epidermis  if  the  shoes  rub  it? 

15.  What  is  the  connection  between  the  hair  and  the  nails  and  the  epi- 
dermis?   What  is  the  name  of  the  pockets  in  the  skin  from  which  the  hair 
grows  ? 

16.  What  is  the  use  of  the  sebaceous  glands? 

17.  What  are  the  papillae?    What  is  their  function? 


HOW  THE  BODY  CLEANSES  ITSELF  135 

18.  Why  is  it  necessary  to  be  careful  not  to  injure  the  skin? 

19.  How  should  wounds  in  the  skin  be  cared  for? 

20.  What  is  the  work  of  the  sweat  glands  ? 

2 1 .  What  is  the  meaning  of  insensible  perspiration  f    Of  sensible  perspira- 
tion f 

22.  When  perspiration  evaporates  from  the  surface  of  the  skin,  what 
does  it  leave  behind  ? 

23.  Why  is  it  necessary  to  bathe  frequently? 


CHAPTER  X 

How  THE  TEMPERATURE  OF  THE  BODY  is  REGULATED 

WHETHER  we  are  shivering  with  cold  in  the  winter  or  perspir- 
ing in  the  warmest  weather,  a  physician's  thermometer  placed 
The  tern-  'm  the  mouth  will  generally  show  that  the  temperature 
perature  of  of  the  body  inside  is  nearly  the  same.  The  ability 
the  body  ±o  maintain  a  certain  temperature  under  all  the 
different  conditions  of  life  is  one  of  the  most  remarkable  of  the 
powers  of  the  human  body.  The  internal  temperature  of  the 
body  is  constantly  maintained  at  about  98.6  degrees.  At  all 
seasons  and  in  all  countries  the  variation  in  temperature  of  a 
healthy  person  is  scarcely  more  than  one  degree.  This  fact 
seems  wonderful  when  we  consider  how  greatly  the  temperature 
of  the  air  may  vary  at  different  seasons  and  in  different  coun- 
tries, —  from  70  degrees  below  zero  in  Arctic  regions  to  130 
degrees  above  in  the  sultry  deserts  of  northern  Africa. 

Things  without  life,  such  as  a  stone  or  a  piece  of  earth,  usually 
take  on  the  temperature  of  the  surrounding  air.  Many  living 
creatures  do  the  same  thing.  The  temperature  of  a  frog,  a 
snake,  a  turtle,  or  an  earthworm  differs  little  from  that  of  its 
surroundings. 

The  only  creatures  which  have  this  great  power  of  main- 
taining a  constant  temperature  in  spite  of  changes  in  the  sur- 
rounding air  are  mammals  and  birds.  These  animals  are  called 
warm-blooded,  because  they  are  usually  warmer  than  surround- 
ing objects;  and  animals  that  have  not  this  power  are  called 

136 


HOW  TEMPERATURE  OF  BODY  IS  REGULATED        137 


cold-blooded,  because  they  usually  feel  colder  to  the  touch  than 
do  warm-blooded  animals. 

The  heat  of  the  body  is  produced  by  a  slow  combustion  of  food, 
and  this  is  taking  place  all  the  time.  This  combustion  goes  on 
chiefly  in  the  muscles  and  is  much  more  active  during  exercise 
than  when  the  body  is  at  rest.  Yet  the 
internal  temperature  of  the  body  during 
rest  and  moderate  exercise  is  the  same, 
although  much  more  heat  is  produced 
during  exercise.  The  loss  of  heat  from 
the  body  takes  place  chiefly  at  the  surface, 
through  the  skin.  A  great  deal  more  heat 
is  lost  from  the  body  when  the  surrounding 
air  is  cold,  yet  the  body  temperature 
remains  the  same.  By  what  means  is  the 
body  temperature  so  perfectly  regulated 
that  it  remains  the  same  under  all  these 
different  conditions  ? 

Think  of  two  ways  in  which  you  may 
regulate  the  temperature  of  a  room.  If  the 
How  the  room  becomes  too  warm,  you 
body  tern-  open  a  window  or  door  to  let 
perature  is  some  of  the  heat  escape.  If  the 
room  is  too  cold,  you  stir  the 
fire,  put  on  more  fuel,  or  open  the  stove  or 
furnace  draughts  so  that  more  heat  will  be 
produced.  You  may  control  the  tempera- 
ture of  a  room  by  regulating  the  amount  of  heat  that  is  pro- 
duced or  by  regulating  the  amount  of  heat  that  escapes.  The 
temperature  of  the  body  is  regulated  in  the  same  way. 

The  marvelous  work  of  regulating  the  temperature  of   the 
body  is  done,  not  by  one  organ  alone,  but  by  several  working 


IF  A  ROOM  BECOMES  TOO 
WARM,  ONE  OPENS  A 
WINDOW  TO  PERMIT  SOME 
OF  THE  HEAT  TO  ESCAPE. 
MUCH  THE  SAME  THING 
OCCURS  WHEN  TOO  MUCH 
HEAT  IS  GENERATED  IN 
THE  BODY,  —  THE  SKIN 
PERMITS  SOME  OF  IT  TO 
ESCAPE. 


138  KEEPING  THE  BODY  IN  HEALTH 

together  under  the  direction  of  the  nerves.  The  nervous  system 
is  the  real  regulator  of  the  body  temperature,  but  the  work  is 
done  by  means  of  three  organs :  the  muscles,  the  blood  ves- 
sels, and  the  sweat  glands. 

The  process  of  heat-making,  which  is  carried  on  in  the  muscles, 
is  regulated  by  certain  nerve  centers  in  the  brain  and  spinal 
cord,  which  are  connected  with  the  muscles  by  nerves,  so  that 
the  making  of  heat  is  under  constant  and  perfect  control.  When 
the  body  is  exposed  to  cold  air  or  water  or  is  in  any  way  cooled 
so  that  the  temperature  of  the  blood  is  lowered,  nerve  centers 
in  the  brain  incite  increased  activity  in  the  heat-making  organs 
and  more  fuel  is  burned  in  the  cells.  In  this  way  the  heat- 
making  process  is  adjusted  to  the  needs  of  the  body. 

When  the  cooling  of  the  body  is  continued  to  such  a  point 
as  to  produce  a  considerable  fall  in  the  temperature  of  the  blood, 
one  usually  feels  chilly  and  begins  to  shiver.  "  Shivering"  con- 
sists in  a  rapid  contraction  of  the  muscles,  in  which  nearly  all 
the  muscles  of  the  body  take  part.  As  muscular  action  is 
always  accompanied  by  the  making  of  heat,  this  contraction  is 
an  automatic  method  of  warming  the  body.  Thus,  shivering 
is  simply  a  natural  method  by  which  the  body  is  exercised  in 
order  to  increase  the  amount  of  heat  production. 

The  loss  of  heat  from  the  body  is  chiefly  at  the  surface,  and 
the  device  for  controlling  this  loss  is  in  the  skin.  There  are  two 
ways  in  which  the  skin  controls  the  escape  of  heat  from  the  body. 
One  is  by  regulating  the  amount  of  blood  that  comes  into  the 
skin.  The  blood  carries  the  heat  from  the  warm  interior  of  the 
body  to  the  surface,  where  it  escapes.  The  temperature  of  the 
skin  is  always  much  lower  than  the  internal  temperature  and 
seldom  rises  above  92  or  93  degrees.  After  cooling,  the  blood 
flows  back  to  the  interior  of  the  body.  In  this  way  the  blood 
equalizes  the  body  temperature. 


HOW  TEMPERATURE   OF  BODY  IS   REGULATED        139 


When  the  body  is  exposed  to  cold,  the  blood  vessels  of  the  skin 
contract  and  shut  out  the  blood,  allowing  only  a  small  quantity 
to  pass  through.  The  blood  is  thus  kept  in  the  warm  interior  of 
the  body.  When  the  blood  becomes  too  hot,  the  Regulation 
blood  vessels  of  the  skin  dilate  and  allow  a  large  ty  the 
amount  of  blood  to  pass  out  into  the  skin  where  it  be- 


comes  cooled.     This  is  the  cause  of  the  flushing  of  glands,  the 
the  face  and  sometimes  even  of  the  whole  body,  when  breath 
it  is  exposed  to  a  warm  atmosphere. 

Through  these  changes  in  the  circulation  of  the  blood  in  the 
skin,  the  heat  loss  may  be 
increased  to  three  or  four 
times  the  usual  amount 
or  lessened  to  the  same 
extent. 

The  other  method  by 
which  the  skin  regulates 
the  loss  of  heat  is  by  the 

J 

work  of  the  sweat  glands. 
We  have  already  learned 
that  the  body  is  cooled  by 
the  evaporation  of  per- 
spiration. Now  evapora- 
tion cannot  take  place 
without  heat.  A  liquid 

in  evaporating  must  take 

up  heat  from  surrounding 

objects.      You  may  easily       GLANDS,  WITH  THEIR  DUCTS  LEADING  TO  THE  SUR- 

j  ,  T    .       i  FACE,   ARE  DISTRIBUTED   THROUGHOUT   THE    SKIN. 

demonstrate  this  by  wet- 

ting one  of  your  hands  and  then  holding  both  hands  in  a 
current  of  dry  air.  Why  does  the  wet  hand  become  so  much 
cooler  than  the  dry  one?  You  may  make  the  same  experiment 


THE    TEMPERATURE    OF   THE    BODY  IS  REGULATED    TO 

A  CONSIDERABLE   EXTENT  BY  THE  PERSPIRATION, 


140  KEEPING  THE  BODY  IN  HEALTH 

by  wetting  one  finger  and  noticing  how  much  cooler  it  becomes 
than  the  rest  of  the  hand.  If  alcohol  or  ether  is  used,  the 
cooling  process  will  be  much  more  marked,  since  both  of  these 
evaporate  much  more  quickly  than  water.  In  the  evapora- 
tion of  a  pound  of  water,  about  1000  heat  units  are  absorbed ; 
that  is,  as  much  heat  is  consumed  in  the  evaporation  of  a 
pound  of  water  as  would  be  required  to  raise  half  a  ton  of 
water  one  degree  in  temperature.  Approximately  two  and  one 
half  pounds  of  water  are  evaporated  from  the  skin  daily,  repre- 
senting a  loss  of  about  2500  heat  units,  or  one  fourth  of  the 
amount  of  heat  generated  in  the  body.  The  loss  of  heat  may 
be  greatly  increased  by  energetic  exercise  or  by  exposure  of  the 
body  to  cool  air. 

The  wonderful  power  of  the  sweat  glands  to  protect  the  body 
from  injury  by  excessive  heat  has  been  shown  by  experiments 
in  which  men  remained  for  some  time  in  a  room  heated  to  260 
degrees  or  to  48  degrees  above  the  boiling  point.  Meat  was 
being  cooked  by  the  heated  air  of  the  room,  an  egg  was  roasted 
hard  in  twenty  minutes,  and  water  soon  boiled ;  but  the  men, 
although  very  uncomfortable,  remained  uninjured.  The  two 
million  little  sweat  glands  of  the  skin  were  hard  at  work  all  the 
time  to  protect  them.  The  evaporation  of  the  water  which 
the  sweat  glands  poured  out  upon  the  skin  in  great  quantities 
cooled  the  skin  and  prevented  it  from  becoming  cooked,  as  it 
otherwise  would  have  been. 

In  order  that  the  evaporation  of  the  sweat  may  take  place 
freely,  the  air  must  be  dry.  In  moist  air,  when  there  is  little 
or  no  evaporation  of  sweat,  the  cooling  of  the  body  is  lessened. 
For  this  reason,  one  is  much  more  liable  to  suffer  from  heat  in  a 
moist  atmosphere,  on  a  "  muggy  "  day,  for  instance,  than  in  a  dry 
atmosphere. 

A  small  amount  of  heat  escapes  from  the  body  in  the  breath 


HOW  TEMPERATURE  OF  BODY  IS  REGULATED        141 

through  the  evaporation  of  moisture  from  the  lungs  and  air 
passages.  Dogs  do  not  sweat,  and  that  is  why  a  dog  pants  when 
overheated  from  exercise  or  warm  atmosphere.  By  the  act  of 
panting,  the  air  is  rapidly  passed  in  and  out  of  the  lungs,  and 
the  increased  evaporation  cools  the  dog's  blood. 

So  constant  must  be  the  body  temperature  in  health  that  any 
variation  from  the  normal,  98.6  degrees,  gives  cause  for  anxiety. 
As  a  result  of  shock  or  of  a  greatly  enfeebled  physical  condi- 
tion, the  temperature  may  fall  below  normal,  through  insufficient 
heat  production  or  too  great  an  escape  of  heat.  More  often 
there  is  a  rise  of  temperature  above  the  normal,  and  then  one  is 
said  to  have  a  fever.  In  fevers,  heat  production  and  loss  are  not 
so  perfectly  controlled  as  in  health,  because  the  heat  centers  are 
disturbed  by  the  poisons  circulating  in  the  blood.  The  sweat 
glands  are  not  so  active  as  usual,  and  the  surplus  heat  does  not 
escape. 

When  one  has  a  fever,  the  temperature  may  be  reduced  by 
sponging  the  body  with  water,  the  evaporation  of  which  will 
carry  off  some  of  the  surplus  heat.    A  hot  bath  may  Artificial 
be  given  or  a  hot  pack  applied,  in  order  to  excite  the  regulation 
activity  of  the  sweat  glands.     It  is  most  important  of  of  temper- 
all  that  water  should  be  freely  drunk  at  such  a  time.  a     e 
A  person  who  has  a  fever  should  drink  a  glassful  of  water  every 
half  hour.     A  little  fruit  juice  of  any  sort  may  be  added  to  the 
water  to  make  it  more  palatable. 

The  heat-regulating  functions  of  the  body  are  not  under  the 
control  of  the  will.  One  cannot  start  or  check  the  perspiration 
or  cause  the  surface  blood  vessels  to  contract  or  dilate  by  an 
effort  of  will.  We  may,  however,  now  that  we  know  how  heat 
is  produced  in  the  body  and  how  it  escapes,  do  various  things  to 
increase  or  lessen  heat  production  or  heat  loss. 

By  active  exercise,  for  instance,  we  can  greatly  increase  the 


142  KEEPING  THE  BODY  IN  HEALTH 

amount  of  heat  produced.  One  exposed  to  the  cold  does  not 
usually  stand  still.  He  walks  or  runs  about,  stamps  his  feet, 
Active  claps  his  hands,  swings  his  arms,  and  engages  in  all 
exercise  sorts  of  muscular  activities  that  increase  heat  produc- 
tion. In  very  warm  weather,  one  is,  on  the  other  hand,  much 
less  active.  In  the  warm  countries,  the  hottest  part  of  the 
day  is  usually  passed  in  sleep,  reducing  as  much  as  possible  the 
amount  of  heat  production. 

Heat  production  is  also  determined  by  the  quantity  and 
quality  of  the  food  eaten.  In  the  Arctic  regions,  men  live 
largely  on  fat,  which  has  the  highest  heat  value  of  any  food, 
while  men  of  the  tropics  live  largely  on  rice  and  fruits,  which 
have  a  low  heat  value.  A  larger  quantity  of  food  is  required 
in  winter  than  in  summer,  especially  by  one  actively  exercising 
out  of  doors.  Why? 

The  escape  of  heat  from  the  body  in  cold  climates  is  greatly 
lessened  by  the  custom  of  living  in  heated  houses.  Some  animals 
Living  in  burrow  into  the  ground  and  make  themselves  nests 
heated  in  which  to  pass  the  winter.  No  animal  but  man, 
homes  however,  provides  itself  with  artificial  heat.  This 
practice  has  many  advantages,  but  it  also  has  some  disadvan- 
tages. What  are  they? 

Do  you  think  there  is  any  danger  from  overheated  rooms? 
Have  you  noticed  that  one  is  very  likely  to  take  cold  in  passing 
from  a  hot  room  into  the  cold  outdoor  air?  Explain.  Over- 
heated rooms  also  have  a  weakening  effect  upon  the  body.  The 
skin  becomes  relaxed,  and  the  body  unduly  sensitive  to  cold. 

Cold  rooms,  or  rooms  insufficiently  heated,  may  also  have  in- 
jurious effects,  because,  in  them,  too  much  heat  may  be  lost  from 
the  body.  When  the  body  is  chilled  and  the  surface  blood  vessels 
contract,  the  blood  is  forced  back  upon  the  organs  within  and  these 
are  likely  to  become  congested;  that  is,  overcharged  with  blood. 


HOW  TEMPERATURE  OF  BODY  IS  REGULATED       143 

The  proper  room  temperature  is  68  degrees.  The  circu- 
lation of  the  blood  will  then  be  well  balanced.  There  will  not 
be  an  excess  of  blood  in  the  skin  or  in  the  internal  organs,  but 
the  blood  will  be  properly  distributed  among  them. 

When  the  skin  is  heated  from  exercise  or  a  hot  atmosphere, 
the  blood  vessels  it  contains  become  filled  with  the  blood  that  is 
forced  into  them.  If  a  person  in  this  condition,  c0ids 
covered  with  perspiration,  sits  in  a  draught  or  in  a  cool  their  cause 
place,  the  blood  vessels  in  the  skin  will  contract  and  cure 
and  the  blood  will  be  forced  inward.  Some  part  of  the  lining 
membrane  of  the  body,  usually  the  nose,  throat,  or  lungs,  will, 
perhaps,  become  congested  with  blood,  and  a  cold  will  be  the 
result.  The  white  cells  in  the  congested  blood  vessels  will  lose 
their  vigor  and  become  inactive,  and  the  microbes  may  gain  the 
advantage  and  make  mischief.  For  this  reason,  a  person  who 
has  a  cold  is  likely  to  take  other  diseases  to  which  he  may  be 
exposed. 

The  best  thing  to  do  when  a  cold  is  developing  is  to  increase 
the  activity  of  the  skin  as  much  as  possible.  This  may  be  done 
in  several  ways  :  (i)  by  vigorous  exercise  which  will  bring  every 
sweat  gland  into  activity ;  (2)  by  a  hot  foot  bath  or  a  full  bath, 
which  will  expand  the  surface  vessels  and  bring  the  blood  to  the 
skin ;  (3)  by  drinking  freely  of  hot  water  or  hot  lemonade,  which 
will  aid  in  starting  perspiration. 

When  the  blood  is  drawn  to  the  surface  of  the  body,  the  deli- 
cate internal  organs  are  relieved  of  the  superfluous  blood  that 
causes  the  congested  condition. 

After  the  hot  bath,  a  short  cold  shower  or  a  quick  cold  rub 
should  be  taken ;  or,  instead  of  either  of  these  methods,  a  pail- 
ful of  cool  water  may  be  poured  over  the  body.  This  cooling 
process  stimulates  the  nerves  of  the  skin  and  prevents  the 
taking  of  cold  afterwards.  It  also  stirs  the  white  blood  cells  to 


144  KEEPING  THE  BODY  IN  HEALTH 

greater  activity  and  so  assists  in  the  work  of  recovering  the 
health. 

Human  beings  living  in  cold  countries  have  learned  that 
the  escape  of  heat  from  the  body  may  be  lessened  by  wearing 
Clothing  clothing.  The  natural  clothing  of  the  body  is  the 
lessens  skin  and  hair.  This  is  true  of  man  as  well  as  of  other 
the  loss  animals.  Savage  tribes  that  live  in  the  mild  cli- 
mate to  which  man  is  naturally  adapted  find  little 
or  no  clothing  necessary  for  either  comfort  or  health. 

But  experiments  have  shown  that  it  is  not  possible  for  the 
body  to  maintain  its  temperature  if  exposed  without  clothing 
to  air  at  a  temperature  lower  than  86  degrees.  The  tempera- 
ture in  which  an  individual  actually  lives  is  that  of  the  air  next 
to  the  body,  inside  of  the  clothing.  Clothes  lessen  the  loss  of 
heat  from  the  body  by  keeping  it  in  a  jacket  of  still  air,  which  is 
an  exceedingly  bad  conductor  of  heat.  Each  additional  gar- 
ment makes  another  "air  jacket."  For  this  reason,  several 
thin  garments  are  much  warmer  than  one  thick  one,  just  as  a 
house  with  double  walls  and  windows,  inclosing  a  layer  of  air, 
is  warmer  than  one  with  single  walls  and  windows,  though  they 
may  be  of  double  thickness.  When  one  throws  off  a  garment 
he  at  the  same  time  removes  one  of  his  "air  jackets." 

Sufficient  clothing  should  be  worn  to  maintain  the  tempera- 
ture of  the  air  in  contact  with  the  body  at  from  80  to  86  de- 
grees. This  requires  for  the  ordinary  man  about  six  to  eight 
pounds  of  clothing  in  the  summer,  and  twice  as  much  in  the 
winter  season  if  he  is  exposed  to  outdoor  temperature.  Those 
who  live  indoors  in  heated  rooms  require,  while  they  remain  in- 
doors, very  little  more  clothing  in  winter  than  in  summer. 

Animals  regulate  their  skin  clothing  to  suit  the  season,  grow- 
ing a  thick  cover  for  protection  in  the  winter  season  and  shedding 
part  of  this  hair  in  the  spring. 


HOW  TEMPERATURE  OF  BODY  IS  REGULATED   145 


A  matter  of  the  highest  importance  is  to  arrange  the  clothing 
on  the  body  so  that  there  will  not  be  too  much  heat  in  some  parts, 
while  other  parts  are  not  sufficiently  protected.  The  arms,  legs, 
and  the  feet  in  particular,  require  special  protection,  because 
they  are  farthest  from  the  heat 
centers,  and  because  they  pre- 
sent a  larger  surface  for  heat 
loss  in  proportion  to  their 
weight  and  the  amount  of 
blood  supplied  to  them  than 
does  the  trunk.  Many  persons 
suffer  greatly  and  are  made 
sick  from  insufficient  clothing 
of  the  limbs  in  the  cold  sea- 
sons, without  being  aware  of 
the  cause  of  their  illness. 
When  the  arms  and  legs  are 
chilled,  the  blood  vessels  contract ;  and,  as  a  consequence,  some 
internal  part  gets  more  than  its  share  of  blood.  Congestion  of 
the  head  and  various  troubles  with  the  internal  organs  may  re- 
sult from  this  source. 

The  material  of  which  clothing  is  made  has  a  very  important 
relation  to  health,  because  different  fabrics  affect  very  differently 
the  escape  'of  heat  from  the  body,  the  absorption 
of  moisture,  and  the  circulation  of  air  about  the  body. 
Linen  absorbs  moisture  more  rapidly  than  does 
wool  and  dries  more  quickly.  This  is  true  of  cot- 
ton to  a  lesser  degree  and  to  a  still  less  degree  of  silk. 

Cotton  has  a  flat  and  twisted  fiber  that  can  be  manufactured 
into  a  much  more  elastic  cloth  than  can  linen,  the  fibers  of  which 
are  cylindrical,  straight,  and  stiff.  Wool  fiber  has  a  jagged, 
scalelike  surface,  and  is  so  soft  and  elastic  that  it  is  difficult 


COTTON  HAS  A  FLAT  AND  TWISTED  FIBER. 


Effect  of 
material 
on  body's 
tempera- 
ture 


146 


KEEPING  THE  BODY  IN  HEALTH 


to  produce  from  it  a  compact  thread;  when  woven  the  cloth 
furnishes  a  great  number  of  air  spaces  between  the  meshes. 
Clothing  made  from  wool  is  both  very  warm  and  very  light. 
Woolen  garments,  however,  are  likely  to  shrink  and  thicken 
when  washed,  unless  very  carefully  laundered.  In  that  case, 
the  air  spaces  between  the  meshes  and  the  elasticity  of  the 

fabric  are  diminished,  until  it 
sometimes  happens  that  woolen 
undergarments  and  hose  after 
frequent  washings  become  al- 
most air  tight,  which  is  not 
good  for  the  body. 

As  the  skin  is  constantly 
throwing  off  moisture,  it  is 
very  important  that  the  cloth- 
ing should  be  able  to  take  it 
up  and  pass  it  out  to  the  air. 
Woolen  fabrics  hold  moisture 

WOOL  FIBER  HAS  A   JAGGED,  SCALE-LIKE   SUR-     for    a     Jong      tjme  ^GOl    Is    OU 

FACE.    WHEN  WOVEN  INTO  CLOTH  THERE 

ARE  A  GREAT  MANY  AIR  SPACES  BETWEEN  this  account  not  well  adapted 

THE  MESHES. 


to  the  skin.  Cotton  is  superior  to  all  other  fabrics  for  this 
purpose.  Linen  stands  next  in  value.  The  fact  that  the  quick 
drying  of  linen  or  cotton  exposes  the  skin  to  rapid  cooling  by 
evaporation  necessitates  the  wearing  of  outer  garments  of  wool 
to  prevent  the  too  rapid  loss  of  heat  during  those  seasons  of 
the  year  when  extra  warmth  is  required. 

The  wearing  of  cotton  next  to  the  body  is  conducive  to 
cleanliness.  Cotton  undergarments  prevent  the  skin  from 
becoming  overheated  and  from  accumulating  undue  moisture 
which  would  relax  the  skin  and  keep  in  a  moist  and  decompos- 
ing state  the  waste  matters  thrown  off  by  it.  Cotton  may  be 


HOW  TEMPERATURE  OF  BODY  IS  REGULATED        147 

worn  at  all  seasons  of  the  year.  It  is  only  necessary  to  pro- 
vide sufficient  outer  clothing  to  secure  the  necessary  warmth. 
An  additional  thick  union  suit  will  afford  better  protection 
than  extra  outer  wraps. 

HEALTH  PROBLEMS 

1.  See  if  you  can  secure  a  physician's  thermometer  to  find  out  your 
internal  temperature.     The  physician  will  tell  you  to  put  the  thermometer 
under  your  tongue.     Why  would  it  not  do  to  put  it  on  the  surface  of  your 
body? 

2.  Note  your  temperature  on  a  hot  day  and  on  a  cooler  day  to  see 
whether  it  varies  according  to  the  weather.     Explain. 

3.  Explain  why  people  who  live  in  cold  countries  are  often  large  and 
ruddy. 

4.  Think  of  some  method  which  has  not  been  mentioned  in  your  lesson 
by  which  you  can  show  to  the  class  that  the  evaporation  of  moisture  is 
a  cooling  process. 

5.  Explain,  as  clearly  as  you  can,  the  process  of  raising  a  half  ton  of 
water  one  degree  in  temperature. 

6.  Is  it  a  good  thing  to  have  very  dry  air  in  winter  when  one  wants  to 
keep  warm?     Is  it  well  to  have  moist  air  in  summer  when  one  wants  to 
keep  cool? 

7.  Why  does  one  feel  cooler  where  there  is  a  wind  than  he  does  where 
it  is  quiet,  even  though  there  is  no  difference  in  the  temperature? 

8.  Why  are  the  people  in  northern  countries  usually  more  active  than 
those  in  the  tropics? 

9.  Have  you  noticed  that  you  are  often  cooler  on  a  hot  day  when  you 
play  or  work  than  when  you  lie  around  in  the  house  ?     Explain. 

10.  Show  why  storm  windows  help  to  keep  a  house  warm,  even  when 
there  is  no  wind. 

IT.  Suppose  you  could  have  an  undergarment  woven  so  that  you  could 
not  see  through  it,  and  could  have  another  which  was  porous,  and  they  were 
both  of  the  same  weight,  which  would  you  choose?  WThy? 

12.  Try  this  experiment :  soak  a  piece  of  wool,  a  piece  of  cotton,  and  a 
piece  of  silk  in  water  until  they  are  thoroughly  wet,  then  take  them  out  and 
see  which  one  will  become  dry  most  rapidly.  Explain. 


148  KEEPING  THE  BODY  IN  HEALTH 

REVIEW  QUESTIONS 

1.  What  would  happen  to  the  body  if  the  internal  temperature  should 
change  very  much  ? 

2.  How  is  the  warmth  of  the  body  kept  up? 

3.  Where  are  the  heat-making  processes  in  the  body  chiefly  carried  on? 
How  is  the  production  of  heat  in  the  body  regulated? 

4.  How  does  the  body  protect  itself  from  undue  heat  or  cold? 

5.  Tell  particularly  about  the  work  of  the  sweat  glands  in  regulating 
the  loss  of  heat. 

6.  Describe  the  experiment  made  by  the  men  who  stayed  in  a  room 
heated  to  260  degrees. 

7.  In  what   sort  of    air   does    perspiration    evaporate  freely?     Why 
does  one  usually  feel  uncomfortable  on  a  muggy  day? 

8.  Why  does  the  temperature  of  the  body  become  higher  when  there 
is  a  fever? 

9.  What  is  a  good  way  to  reduce  the  temperature  of  the  body  when 
there  is  a  fever? 

10.  What  is  the  influence  of  exercise  upon  the  making  of  heat  in  the 
body? 

11.  Why  does  one  usually  feel  like  being  inactive  on  a  very  hot  day? 

12.  How  does  the  kind  of  food  one  eats  affect  the  making  of  heat  in 
his  body? 

13.  Why  is  one  likely  to  take  cold  if  he  lives  in  a  house  that  is  over- 
heated? 

14.  Why  should  one  always  follow  a  hot  bath  with  a  cold  spray  or  a 
dash  of  cold  water  ? 

15.  How  does  clothing  check  the  loss  of  heat? 

16.  Why  is  it  better  to  wear  several  light  garments  in  winter  than  one 
very  thick  and  heavy  one  ? 

17.  What  parts  of  the  body  should  be  clothed  particularly  well  in  winter, 
and  why  ? 

18.  What  kind  of  clothing  should  be  avoided?    Why? 


CHAPTER  XI 

THE  FRAMEWORK  OF  THE  BODY 

SOME  of  the  work  of  the  body  —  that  of  supporting  itself  — 
is  too  heavy  for  the  soft  cells  to  do  alone.  They  therefore  build 
up  around  themselves  solid  structures,  in  much  the  The  nature 
same  way  that  a  snail  or  a  turtle  builds  its  shell  out  and  uses  of 
of  its  own  body.  Bone  and  cartilage,  which  make  bones 
the  solid  frame  work  of  the  body,  are  formed  in  this  way. 

The  skeleton  of  a  new-born  baby  is  composed  almost  wholly 
M  cartilage,  which,  as  you  know,  is  not  so  hard  as  bone.  Car- 
tilage is  pliable  and  for  that  reason  the  bones  of  a  little  child 
may  be  easily  bent. 

The  bones  as  they  grow  are  gradually  hardened  through  the 
building  of  lime  into  them  by  the  bone  cells.  By  the  time  they 
are  full  grown  only  a  thin  layer  of  cartilage  on  the  ends  of  the 
bones  remains.  In  order  that  they  may  be  properly  developed, 
the  food,  especially  of  young  children,  should  contain  a  sufficient 
quantity  of  lime.  Milk  and  whole- wheat  bread  are  good  bone- 
building  foods.  Why? 

If  the  lime  or  mineral  matter  is  dissolved  out  of  a  fresh  bone 
by  acid,  the  animal  part  that  remains  will  be  found  so  flexible 
that  the  bone,  if  long  and  slender,  may  be  easily  tied  in  a  knot. 
The  more  lime  there  is  in  bones,  the  less  pliable  and  the  more 
brittle  they  become.  The  proportion  of  lime  in  the  bones 
seems  to  increase  from  year  to  year  through  life.  For  this 
reason  the  bones  of  aged  persons  are  very'  easily  broken. 

I4Q 


Spinal  Co/urn  n 
Cer  vico/ Region 

C/a  vic/e 
'Collar  BoneJ 


Sternum 
(Breast  BoneJ 

Ribs 


Pe/v/cBone 


Carpal 'Bones 
Me  lacarpalBones 
Pholonges 

femur- 


fcnee   Cap) 


Cranium 

JVasa/Bones 
Ma  far  fCh  e  ek£on  ej 
Sup  er/or  Max/Vary  Bones 
•Inferior  Maxi//ary  Bones 


Humerus 
Spinal  Column 


CarpalBones 


Ttbia 
F/bu/a 


Tarsa/Bones 

'Metatarsa/Bone3 
Phalanges 

SEE  IF  vou  CAN  TELL   HOW  EACH   BONE    IN  THE   SKELETON   is   USED   IN  A  PERSON'S 

DAILY    WORK    OR    PLAY. 


THE  FRAMEWORK  OF  THE  BODY 


Bones  are  covered  by  a  tough  membrane  called  the  periosteum, 
which  contains  a  few  nerves,  and  numerous  blood  vessels  through 
which  the  bone  is  nourished  and  developed. 

If  the  large  bones  of  the  human  body  were  solid,  they  would 
be  very  much  heavier  without  being  much  stronger.  Of  course 
it  is  necessary  that  they  should  be 
not  only  firm  and  strong  but  light 
enough  to  be  easily  moved.  If 
you  look  at  the  picture  of  a  half 
section  of  a  long  bone,  you  will 
see  that  it  is  only  the  outer  layer 
that  is  composed  of  solid  bone.  Of 
what  is  the  inner  layer  composed  ? 
You  should  note  especially  that  in 
the  center  there  is  a  canal  or  hol- 
low space. 

Do  you  see  that  cavities  in  the 


Spongy  Bon* 
Containing 
fied Marrow. 


ffarj  Bon* 


•Per/osteum 


Cov/ty 


bones  not  only  give  lightness,  but  THIS  PICIDRE  SHOWS  HOW  raE  JNTE5IOR 
that  they  also  increase  the  strength      OF  A  LONG  BONE  is  CONSTRUCTED. 

r   . ,     -,        -^    /-.  i  •      IS  THERE  ANY  ADVANTAGE  IN  HAVING 

of  the  bones?     Can  you  explain      THE  INTERIOR  SPONGY? 
why? 

An  experiment  with  a  sheet  of  paper  and  a  book  will  show 
that  when  the  paper  is  rolled  into  a  hollow  cylinder,  it  will  sup- 
port more  weight  than  in  any  other  form.  Mention,  in  addition 
to  bone,  other  instances  in  which  nature  makes  use  of  this  plan 
to  secure  a  combination  of  lightness  and  strength.  Think  of 
some  ways  in  which  man  makes  use  of  it  also. 

You  will  be  interested  to  learn  that  the  blood  is  largely  formed 
in  the  bones.  The  cavities  of  the  long  bones  are  filled  with  a 
substance  called  marrow,  containing  nerves  and  blood  vessels  and 
large  quantities  of  fat.  The  fat  gives  it  a  yellow  color.  In  the 
smaller  cavities  of  the  spongy  bone  the  marrow  contains  less  fat 


152  KEEPING  THE  BODY  IN  HEALTH 

and  is  of  a  red  color.  The  red  blood  corpuscles  are  produced  in 
the  red  marrow  of  the  bones,  while  the  white  corpuscles  are  formed 
to  some  extent  in  the  marrow  which  fills  the  hollow  spaces  of  the 
long  bones. 

Without  a  skeleton,  the  body  would  not  be  able  to  hold  itself 
upright.  One  of  the  chief  uses  of  the  bones  is,  therefore,  to 
support  the  body. 

It  is  easy  to  see,  is  it  not,  that  without  the  bones  the  various 
movements  of  the  different  parts  of  the  body,  as  in  walking, 
raising  the  arms,  and  so  on,  would  not  be  possible?  The  bones 
aid  in  moving  the  body  and  its  various  parts.  Each  bone  has 
roughened  places  and  ridges  to  which  muscles  are  attached,  and 
the  bones  thus  provide  levers  by  means  of  which  the  muscles  are 
able  to  move  the  body. 

Another  important  use  of  the  bones  is  to  protect  from  injury 
the  delicate  and  sensitive  parts  of  the  body.  You  can  feel  the 
strong  box  that  the  bones  of  your  head  form  for  the  protection 
of  your  brain.  The  spinal  cord,  which  is  an  extension  of  the 
brain,  is  guarded  by  the  bony  tube  called  the  spinal  column. 
You  can  feel  also  the  strong  framework  of  bone  that  protects 
the  lungs  and  the  heart. 

The  body  of  a  new-born  baby  has  as  many  bones  as  that  of  a 
full-grown  man  —  206.  The  bones  are  of  different  sizes  and 
shapes,  according  to  the  use  that  is  to  be  made  of  them.  Some 
are  long,  as  those  in  the  legs  and  arms;  some  short,  as  in  the 
wrist ;  some  flat,  as  in  the  upper  part  of  the  skull ;  some  curved, 
as  in  the  ribs.  By  studying  the  picture  of  the  skeleton  and 
comparing  it  with  your  own  body,  you  can  easily  locate  all  the 
principal  bones  and  find  out,  if  you  wish,  the  names  that  have 
been  given  to  them. 

The  most  important  and  interesting  of  the  bony  structures 
of  the  body  is  the  spinal  column,  It  is  necessary  that  it  should 


THE  FRAMEWORK  OF  THE  BODY 


153 


Cerv/ca/ 


Thoracic 


be  strong  enough  to  support  the  trunk  and  the  head  and  protect 
the  spinal  cord.  It  must  be  flexible  enough  to  bend  with  ease 
in  any  direction  with  the  movements 
of  the  trunk,  yet  in  such  a  manner 
that  the  delicate  spinal  cord  within 
The  spinal  it  will  not  be  injured.  This 
column  wonderful  combination  of 
uses  is  accomplished  by  the  arrange- 
ment of  a  number  of  separate  ringlike 
bones,  one  above  another,  bound  to- 
gether with  bands  of  strong  connective 
tissue.  These  separate  ringlike  bones 
are  called  the  vertebra.  The  bony  col-  Or  Dorse/ 
umn  with  the  canal  for  the  spinal  cord 
running  through  it,  is  formed  by  the 
twenty-four  vertebrae  arranged  one  above 
the  other,  as  is  shown  in  the  illustration. 
The  vertebrae  are  separated  from 
each  other  by  means  of  disks  com- 
posed of  very  elastic  cartilage.  These 
act  as  buffers  to  prevent  friction  and 

Buffers  to     Jarring    which    miSht     inJure 
the  brain.     A  person  who  is 

much    on    his    feet    becomes 
shorter  during  the  day  by  the 
thinning  of  the  cartilages  between  the 

.....  THE   SPINAL  COLUMN  IS  A  BONY 

vertebrae;    but   he    regains    his   height      TUBE  WHICH  PROTECTS  THE 
during    the    night.     Most    persons    are       SPINAL  CORD-    NOTICE  THE 

^         ^  RINGLIKE   BONES  — THE   VER- 

half  an  inch  taller  in  the  morning  than      TEBR^  —  so  PLACED  UPON 

.     ,  ONE  ANOTHER  THAT  A  PERSON 

at  nignt.  CAN  BEND  PREELY  IN  ANY  DI- 

You  will  notice  in  the   picture   that       RECTION  AND  NOT  <NJURE 

.  THE    DELICATE     CORD     WITH- 

the  spinal  column  is  not  straight  but      IN. 


prevent 
jarring  in 
the  body 


Sacra/ 


154 


KEEPING  THE  BODY  IN  HEALTH 


•Sp/nof  Cord 


NOTICE  THE  RINGS  OF  CARTILAGE  BETWEEN  THE 
VERTEBRA.  NOTE  ALSO  HOW  THE  SPINAL  CORD 
IS  PROTECTED. 


forms  a  graceful  double  curve.  It  is  upon  the  preservation 
of  the  natural  curves  of  the  spine  that  the  poise  and  graceful 
carriage  of  the  body  chiefly  depend.  These  curves  also  aid  in 

giving  springiness  to  the 
spinal  column  and  so  pre- 
vent the  jarring  of  the 
head  in  walking  or  run- 
ning. 

Notice  the  difference 
in  the  amount  of  jar  the 
body  receives  in  jumping 
with  the  legs  straight  and 
stiff  and  with  the  legs  bent 
at  the  knees ;  also  the  difference  in  the  jarring  of  the  hand  when 
the  ground  is  struck  with  a  straight  stick  and  with  a  curved  one. 
The  curves  in  the  spine,  the  arch  of  the  foot,  and  the  bending 
of  the  knee,  as  well  as  the  cartilages  separating  the  vertebrae,  all 
aid  in  protecting  the  brain  by  giving  greater  springiness  to  the 
skeleton. 

If  the  spinal  column  is  broken  it  is  quite  impossible  to  stand 
or  walk,  because  there  is  no  support  for  the  trunk,  and  the 
spinal  cord  which  controls  the  movements  of  the  muscles  is 
injured. 

If  the  bony  framework  of  the  body  were  all  united  in  one 
piece,  no  movement  of  the  different  parts  of  the  body  would  be 
The  possible.  If,  on  the  other  hand,  it  were  composed  of 

joints  disconnected  bones,  there  would  be  no  support  for 

the  body  as  a  whole  and  it  would  not  be  able  to  stand  upright. 
It  is  necessary  that  the  bones  should  be  joined  together,  but  in 
such  a  way  that  the  free  movements  of  the  parts  will  be 
possible.  The  places  where  the  bones  are  united  are  called 
joints. 


THE   FRAMEWORK  OF  THE  BODY 


155 


Where  great  strength  but  no  movement  is  required,  the  bones 
are  solidly  united  by  immovable  joints.     Since  there  is  no  move- 


Parieto, 


Sphenoid 
tfasa/Itones 
Lachryma/ Bone 
Efhmoid  Bone 


(Upper  Jaw 


'ccipit 


'Mastoid  Process 

Inferior  Afaxiffary 
(Lower  JawJ 


MOST  OF  THE  JOINTS  IN  THE  HUMAN  SKULL  ARE  IMMOVABLE.    Is  THIS  A  GOODi  ARRANGEMENT? 

WHY? 

ment  at  these  joints,  we  cannot  detect  them  in  our  own  bodies, 
but  they  may  easily  be  seen  in  the  head  of  a  skeleton. 

In  an  immovable  joint,  the  bones  are  firmly  united  by  a  piece 
of  cartilage  that  grows  between  them.  In  a  movable  joint,  a 
thin  layer  of  cartilage  covers  the  end  of  each  bone,  and  this  is 
kept  lubricated,  or  moist,  by  an  oily  fluid  poured  out  by  a  delicate 
membrane  that  incloses  the  joint.  This  enables  the  joint  to 
work  smoothly. 

The  joints  are  bound  together  by  tough  bands  of  connective 
tissue  called  ligaments.  Besides  holding  the  bones  together, 
these  ligaments  also  limit  the  movements  of  the  joints. 

There  are  several  kinds  of  movable  joints.  In  the  ball-and- 
socket  joint,  the  rounded  end  of  one  bone  fits  into  a  cuplike 
hollow  in  another  bone.  This  kind  of  joint  is  found  in  the 
shoulder  and  the  hips.  It  gives  the  greatest  freedom  of  motion, 


156 


KEEPING  THE  BODY  IN  HEALTH 


Acefabufum 


allowing  movement  in  all  directions,  as  you  may  see  by  swinging 
your  arms  or  legs.     Hinge  joints,  examples  of  which  are  found 

in  the  elbow  and  the 
finger,  allow  movement 
only  in  two  opposite 
directions.  In  gliding 
joints,  the  bones  move 
slightly  upon  each  other, 
as  at  the  wrist  and  ankle. 
The  vertebrae  have  a 
special  kind  of  joint. 
They  rock  back  and  forth 
on  each  other,  as  they 
are  pulled  by  the  muscles 

-femur 


/turner  us  • 


THE  HIF   JOINT    IS  A    3OOD     EXAMPLE  OF   THE   BALL- 
AND-SOCKET    JOINT.       WHAT     MOVEMENTS    AXE 

MADE    POSSIBLE    BY   THIS    KIND    OF    JOINT? 


that  control  them,  the  amount 
of  movement  being  limited  by 
the  ligaments  that  hold  them 
together. 

In  consequence  of  a  fall  or  a 
blow,  the  end  of  a  bone  is  some- 
Injuries  of  times  dislocated  or 
the  bones  "put  out  of  joint." 
and  joints  The  iigaments  about 
the  joint  are  torn,  and  the  bone 
slips  out  of  place.  On  the 
occurrence  of  such  an  accident, 


Pad/us 


17/na 


THE    ELBOW    JOINT    ILLUSTRATES    THE 
HINGE  JOINT.    WHAT  MOVEMENTS  ARE 

MADE     POSSIBLE     BY     THIS     KIND      OF 
JOINT? 


THE   FRAMEWORK  OF  THE  BODY 


157 


a   physician   should   be    called   at  once   to   replace    the    bone 
before    the   parts   become   swollen.     Why   will   they   swell? 

A  sprain  is  an  injury  due 

to  a  joint's  being  so  badly  cr/na— ^  ^  j^^-ff^/us 
strained  that  a  ligament  is 
torn  from  its  fastenings  to 
the  bone.  Bathing  in  water 
as  hot  as  can  be  borne  will 
keep  down  the  swelling  and 
relieve  the  pain.  Why?  Ele- 
vation of  the  injured  member 


J//um 


WrfsfBenes 


femur 


IN  A  SPRAIN,  THE  LIGAMENT  THAT  HOLDS  THE 
BONES  IN  PROPER  POSITION  IN  A  JOINT  IS 
STRETCHED  OR  TORN.  IF  THE  HIP  LIGA- 
MENT —  SHOWN  IN  THE  PICTURE  —  SHOULD 
BE  TORN  THE  HIP  WOULD  BE  SPRAINED. 


THE  BONES  IN  THE  WPIST  PERMIT  OF  A  SLIGHT 
GLIDING  MOVEMENT  UPON  EACH  OTHER. 


will  also  help  to  keep  down 
the  inflammation.     Why? 

When  a  bone  is  broken, 
the  muscles  often  draw  the 
ends  of  the  broken  bone  apart 
and  a  physician  is  required 
to  put  the  parts  back  into 
their  proper  position.  There 
may  be  sharp  points  on  the 
ends  of  the  broken  bones, 
which  are  likely  to  tear  the 
tissues  if  the  limb  is  bent  at 
the  broken  point.  On  this 
account,  great  care  should  be 
taken  to  keep  the  limb  per- 


158 


KEEPING  THE  BODY  IN  HEALTH 


fectly  quiet  until  the  physician  arrives.  After  being  "set,"  the 
ends  of  the  bones  must  be  held  in  position  by  splints  and 
bandages  until  Nature  has  time  to  cement  the  parts  together 

by  the  hardening  of  a  sub- 
stance poured  out  between 
and  around  the  ends  of 
the  broken  bone.  This 
substance  gradually  be- 
comes firm,  making  the 
bone  nearly  as  good  as  be- 
fore. 

The  effects  of  tobacco 
poison  in  preventing 
proper  development  of  the 
bones  is  so  marked  that 
even  those  who  assent  to 
its  use  by  adults  con- 
demn its  use  by  growing 
boys.  We  have  already 
seen  that  tobacco  injures 
the  heart,  the  lungs,  and 
the  digestive  organs,  so 
that  no  part  of  the  body 
gets  its  proper  supply  of 
food  and  oxygen.  The 
bones  suffer,  as  well  as 
the  rest  of  the  body,  from 

this  lack.  Besides  this,  the  tobacco  poison  seems  to  have  a 
special  effect  in  injuring  the  bone  cells  and  checking  the  develop- 
ment of  the  bones.  A  boy  who  at  an  early  age  begins  to  smoke 
cigarettes  is  likely  to  become  dwarfed  and  stunted  in  body  as 
well  as  in  mind. 


WHEN  A  BONE  is  BROKEN  A  SURGEON  SHOULD  "SET" 

IT,  AND  THE  PARTS  SHOULD  BE  HELD  IN  PLACE  BY 
SPLINTS  AND  BANDAGES  UNTIL  NATURE  CAN  CE- 
MENT THEM  TOGETHER.  THE  ILLUSTRATION  IS 
AN  X-RAY  PICTURE  OF  A  BROKEN  BONE. 


Fronta/ti 

Orbicufar/s 
P&fie  brarum 

Orb/'ca/ar/'s  Or/'s 
Buccinator 
Trapezius 


J3iceps 

Triceps 

Sracnfo  -JRadiafts 

/tec  t us  A  bdomina/is 


Pectinefus 

Rectus  Femoris 
Sorter/us 
Vasfus  Jnternus 

So/eus 
Gas  fro  en  em /'us 


Temporaf 

Masseter 
Ster/iomasto/d 


Pectora/is  Major 

'errafus  Magnus 

Ob/t'quu$  Externus 
Abdominis 

Tensor  Fasciaer 
Femoris 


Vasfus  Externus 


'Extensor  JL  ongus 
T/bia/isAnticus 
*Peronc  us  Lonyus 


THIS  PICTURE  SHOWS  THE  MUSCLES  OF  THE  BODY 


i6o 


KEEPING  THE  BODY  IN  HEALTH 


If  you  should  fasten  the  bones  of  a  skeleton  together  with 
artificial  joints  and  then  should  try  to  make  this  framework 
Keeping  stand  upright,  you  would  find  that  you  could  not 
straight  do  so ;  it  would  all  fall  together  into  a  heap  of  bones. 
There  must  be  something  besides  the  joints  to  hold  the  bones 
together  and  keep  them  in  their  proper  position.  This  work 
is  done  by  the  muscles.  The  skeleton  could  no  more  stand  alone 
without  the  aid  of  the  muscles  than  the  muscles  could  stand 
without  the  skeleton. 
It  is  of  great  importance  that  every  group  of  muscles  in  the 

body  should  be  well 

developed  so  that 
the  skeleton  may 
be  held  correctly. 
It  should  be  sup- 
ported equally  on 
every  side,  like  the 
masts  and  spars  of 
a  full-rigged  vessel. 
This  is  necessary, 
in  the  first  place, 
that  one  may  have 
a  good  appearance. 
We  bear  in  our 
bodies  a  record  of 
our  habits  that 
may  be  easily  read 
by  a  trained  eye. 
A  slouching  body 
and  a  shuffling  walk 

create    a   most    unfavorable   impression  of  carelessness,    lazi- 
ness, and  lack  of  dignity  and  self-respect.    A  boy  who  walks 


WE  BEAR  IN  OUR  BODIES  AS  WE  GROW  OLDER  A  RECORD  OF 
THE  WAY  WE  HAVE  STOOD,  WALKED,  AND  SAT.  WlLL  THIS 
BOY  HAVE  A  FINE  RECORD? 


THE  FRAMEWORK  OF  THE  BODY 


161 


with  head  erect  and  shoulders  well  squared  gives  an  impression 
of  energy  and  self-respect  which  is  of  great  advantage  to  him.  A 
girl  with  a  fine  carriage  and  graceful  walk  makes  a  much  finer 
appearance  than  one  who  neglects 
to  hold  herself  erect  and  who  walks 
with  a  careless  gait. 

We  are  in  some  respects  the 
architects  of  our  own  bodies.  It 
is  more  or  less  in  our  power  to 
determine  the  shape  of  the  body. 
Especially  in  youth  when  the 
bones  are  pliable  and  the  muscles 
supple,  we  may,  according  to  our 
habits,  influence  the  position  of 
the  bones  and  their  relations  to 
each  other.  We  may  then  deter- 
mine whether  we  shall  have  well- 
shaped  bodies  and  erect  carnage 
that  will  recommend  us  to  others 
or  awkward  carriage  and  ungainly 
bodies  that  will  always  be  a  handi- 
cap to  us. 

The   symmetrical  development 

of  the  body  is  of  even  more  importance  for  the  sake  of  health 
than  for  that  of  a  good  appearance.  An  external  deformity 
usually  means  a  corresponding  internal  deformity;  the  latter 
is  of  far  greater  importance  than  the  former.  Round  shoulders, 
for  instance,  are  always  accompanied  by  a  flat  chest.  This 
means  that  the  lungs  are  compressed  and,  therefore,  that  the 
breathing  capacity  is  lessened. 

It  is  only  by  exercise  that  the  suppleness  of  the  body,  the 
elasticity  of  the  muscles,  and  the  flexibility  of  the  tendons  and 


A  FINE  CARRIAGE  IS  IMPORTANT  BOTH  TO 
HEALTH  AND  TO  APPEARANCE. 


THE  EXERCISES  SHOWN    IN    THE    PICTURES    ARE    FINE  TOR    GOOD   POSTURE. 


THE   FRAMEWORK  OF  THE   BODY 


163 


ligaments  can  be  preserved.     If  the  muscles  of  a  certain  part  of 
the  body  are  not  used  in  such  a  manner  as  to  stretch  them,  they 
may  become   shortened    and,   after    this,   stretching  How  de_ 
them  will  be  impossible.     If  the  arm  be  kept  bent  formities 
for  a  long  time,  it  may  become  impossible  to  straighten  are  caused 
it,  because  the  muscles  of  the  inner  side  of  the  arm  will  have 
become  shortened  through  not  being  stretched.     In  this  way, 
deformities  may  be  produced  when  bones  have    been    pulled 
out  of  place,  for  the  bones  may  be  permanently  held  in  a  wrong 
position  by  a  shortening  of  the  muscles. 

The  vertebrae  of  the  spinal  column  are  moved  by  the  contract- 
ing and  lengthening  of  the  mus-    i < 

cles  attached  to  them.  When 
the  spine  is  curved  on  the  left 
side,  the  muscles  on  the  right 
side  contract  and  are  short- 
ened, and  a  curvature  of  the 
right  side  means  a  shortening 
of  the  muscles  on  the  left  side. 
When  the  body,  in  sitting, 
standing,  or  working,  is  habit- 
ually held  in  an  improper  posi- 
tion, some  of  the  muscles  may 
become  permanently  short- 
ened, causing  a  life-long  de- 
formity, known  as  spinal 
curvature .  A  backward  curva- 
ture of  the  spine,  manifested 
by  round  shoulders,  a  flat  or 
hollow  chest,  and  forward 

carriage  of  the  head,  is  by  far  the  most  common  form  of  spinal 
curvature,     If  the  muscles  of  the  back  are  relaxed,  the  spine 


WHEN  A  GIRL  SLOUCHES  IN  HER  CHAIR,  AS  THIS 
ONE  DOES,  SHE  WILL  BECOME  NARROW- 
CHESTED  AND  SHE  WILL  FEEL  AS  DUMPISH 
AS  SHE  LOOKS. 


164  KEEPING  THE  BODY  IN  HEALTH 

naturally  forms  a  backward  curve.  This  is  what  makes  the 
chest  flat.  The  trouble  is  not  in  the  chest,  but  in  the  spine,  and 
the  curvature  of  the  spine  is  due  to  the  relaxation  of  the  muscles 
of  the  back,  which  allows  the  spine  to  bend  unduly. 

It  is  very  important  to  remember  that  the  bones  are  affected 
by  what  we  eat.  In  order  that  the  bones  may  grow  large  and 
strong,  the  food  must  contain  an  abundance  of  lime.  This  is 
found  in  all  kinds  of  green  vegetables,  such  as  turnip  tops,  beet 
tops,  greens  of  all  sorts,  in  milk,  in  yolk  of  eggs,  and  in  such 
whole  grains  as  oatmeal  and  wheat  flakes.  Almost  no  lime  is 
found  in  bread  made  with  fine  flour,  in  rice,  in  the  specially  pre- 
pared corn  meal,  in  potato,  or  meat,  and  none  at  all  in  sugar 
or  honey. 

In  the  back  of  this  book  will  be  found  a  table  giving  the  foods 
that  are  richest  in  lime  and  iron. 

Every  growing  child  needs  daily  not  less  than  fifteen  or  twenty 
grains  of  lime.  The  quantity  of  food  required  to  furnish  this 
amount  is  shown  in  the  table  referred  to  above. 


HEALTH  PROBLEMS 

1.  Suppose  a  boy  five   years   old   and   a   youth    twenty  years   old 
should  accidentally  slip  when  climbing  a  tree  and  fall  a  distance  of  fifteen 
feet.    Do  you   think  it   probable   that   either  would    break    the    bones 
in  his  leg  or  in  some  other  part  of  his  body  ?    Which  do  you  think  would 
be  more  likely  to  escape  injury?    Explain. 

2.  Suppose  a  man  fifty  years  of  age  were  climbing  in  place  of  the  boy 
of  five,  which  one  of  the  persons  falling  would  then  be  more  likely  to  suffer  ? 

3.  Suppose  a  boy  of  five,  a  young  man  of  twenty,  and  a  man  of  fifty 
years  should  each  break  a  bone  in  his  leg.    Which  one  of  the  three  per- 
sons do  you  think  would  recover  soonest  ?    Explain. 

4.  Try  the  experiment  of  taking  the  lime  out  of  a  bone  and  notice 
what  happens  to  it. 


THE   FRAMEWORK  OF  THE   BODY  165 

5.  Try  the  experiment  of  burning  the  animal  part  out  of  a  bone  and 
notice  what  happens  to  it. 

6.  Try  the  experiment  of  holding  your  body  perfectly  stiff  and  then 
jumping  up  and  down  on  your  heels,  though  not  very  high,  of  course.     How 
do  you  feel?     What  reason  can  you  give  for  this  experience? 

7.  Point  to  some  immovable  joints  in  your  own  body.     Why  did  Nature 
not  make  them  movable? 

8.  A  boy  I  know  had  his  leg  broken  in  a  football  game.     He  did  not 
have  the  surgeon  called  at  once.     It  is  now  six  months  since  the  accident 
occurred,  and  the  break  has  not  yet  healed,  though  otherwise  he  is  perfectly 
healthy.     What  do  you  think  may  be  the  explanation  of  this? 

9.  Mention  some  deformities  you  have  noticed  which  could  have  been 
avoided  by  good  habits  of  sitting,  standing,  and  walking. 


REVIEW  QUESTIONS 

1.  What  makes  up  the  framework  of  the  body? 

2.  Of  what  is  the  skeleton  of  a  new-born  baby  composed? 

3.  What  is  the  cause  of  such  deformities  as  knock-knee  and  bowleg? 

4.  What  makes  the  bones  hard?    Describe  the  different  parts  of  which 
the  bone  is  composed. 

5.  What  kind  of  food  do  young  children  need  in  order  to  build  their 
bones? 

6.  What  is  the  periosteum? 

7.  Why  did  nature  not  make  the  large  bones  of  the  body  solid? 

8.  How  does  nature  secure  lightness  and  strength  in  bones? 

9.  WTiat  are  the  uses  of  the  skeleton? 

10.  By  what  arrangement  do  the  muscles  move  the  bones? 

11.  What  is  the  spinal  column? 

12.  How  is  the  spinal  column  made   flexible? 

13.  What  are  bones  in  the  spinal  column  called? 

14.  What  is  the  use  of  the  disks  that  separate  the  vertebrae? 

15.  Of  what  value  to  the  body  is  the  double  curve  in  the  spine? 

1 6.  What  are  the  ways  in  which  Nature  tries  to  prevent  too  great  jarring 
of  the  brain  when  one  walks,  runs,  or  jumps? 

17.  If  the  spinal  column  should  be  broken,  what  would  happen  to  the 
body? 


i66  KEEPING  THE  BODY  IN  HEALTH 

18.  What  is  the  purpose  of  the  joints  that  connect  the  bones?    What 
is  meant  by  immovable  joints?     Mention  some  of  these  joints.    What  is 
meant  by  movable  joints?     Mention  some  of  these. 

19.  What  is  the  use  of  the  ligaments  in  the  body? 

20.  Give  an  example  of  the  ball  and  socket  joint ;   of  the  hinge  joint : 
of  the  sliding  joint. 

21.  What  is  a  sprain?    How  should  one  treat  a  sprain? 

22.  What  should  be  done  in  case  a  bone  is  broken? 

23.  What  is  the  effect  of  tobacco  on  the  bones? 

24.  What  is  needed  besides  bones  and  joints  to  keep  the  body  upright? 


CHAPTER   XII 
THE  BODY  IN  MOTION 

EVERY  movement  of  a  living  creature  is  made  by  means  of 
muscles.  The  flight  of  a  bird  in  the  air,  the  rapid  moving  of  an 
insect's  wings,  the  gliding  of  a  snake  along  the  ground,  —  all  ani- 
mal movements  of  whatever  kind  are  made  by  means  of  muscles. 

There  are  two  kinds  of  muscles  in  the  human  body:  those 
which  are  under  the  control  of  one's  will,  called  voluntary 
muscles ;  and  the  involuntary  muscles  wMch  one  Kinds  of 
cannot  control  by  just  willing  to  do  so.  Five  hundred  muscles 
pairs  of  voluntary  muscles  are  the  servants  of  the  will  in  per- 
forming the  different  kinds  of  work  of  which  the  body  is  capable. 
The  number  of  the  involuntary  muscles  is  too  great  to  be  esti- 
mated. The  skin  is  a  perfect  network  of  little  muscles.  Every 
hair  has  a  minute  muscle  attached  to  it  by  means  of  which  it 
may  be  made  to  stand  erect.  The  stomach  is  a  muscular  sac, 
the  intestines  a  muscular  tube,  the  air  tubes  of  the  lungs  have 
muscular  walls,  and  the  heart,  the  great  pumping  organ  of  the 
circulation,  is  a  wonderful  muscular  engine. 

The  involuntary  muscles  act  according  to  the  needs  of  the 
body  and  quite  independent  of  one's  will.  They  are  at  work 
for  us  when  we  are  asleep,  as  well  as  when  we  are  awake,  keeping 
the  heart  beating  and  the  lungs  active.  When  food  is  swallowed, 
it  is  seized  by  the  involuntary  muscles  and  carried  into  the 
stomach,  worked  upon,  and  moved  from  point  to  point  until  it 
is  digested.  By  means  of  these  muscles,  the  blood  is  circulated 
and  the  supply  to  each  part  is  regulated.  All  their  work  is  done 

167 


168  KEEPING  THE  BODY  IN  HEALTH 

with  faithfulness   and  loyalty  to  the   well-being  of  the  body, 
even  when  the  voluntary  muscles  controlled  by  the  will  are 


MUSCLES  HAVE  DIFFERENT  SHAPES  AND  SIZES  ACCORDING  TO  THE  SPECIAL  WORK  EACH  HAS 

TO  DO. 

working  against  the  body's  interests.     Think  of  some  instances 
that  will  illustrate  this. 

The  muscles  are  of  different  shapes  and  sizes,  according  to 
the  work  for  which  they  are  designed.     Some  are  shaped  like  a 
spindle,  some  like  a  feather,  some  like  a  fan, 
and  still  others  are  ring  shaped. 

The   cells   which    compose    the   voluntary 
muscles  are  the  largest   and  most  active  in 
.    the   entire   body.      They   form    the   muscle 
fibers,    which    are    long,    slender   structures. 
They  have  the  power  to   contract,  or  draw 
themselves  up  as   a  worm  does  in  crawling, 
becoming  shorter  and  thicker.      The  muscle 
MUSCLE  FIBERS    HAVE  fibers  are  held  together  by  a  framework  of 
THE  POWER  TO  CON-  connective    tissue,    which    divides    the    cells 

TRACT,    BECOMING      .  .  •  i  11 

SHORTER  AND  THICKER,  into  groups  and  ties  them  up  into  bundles. 


°f   mCat   ^   mUSClC-        A 

BY  CONNECTIVE  TISSUE,  piece  of  lean  corned  beef  may  be  easily  sepa- 


THE  BODY  IN  MOTION 


169 


How 
muscles 
are 

attached 
to  bones 


rated  into  small  bundles.  These  bundles  may,  by  the  use  of 
needles,  be  separated  into  bundles  still  smaller.  These  last 
small  threads  are  the  muscle  fibers. 

Nearly  all  the  voluntary  muscles  are  attached  to  the  frame- 
work of  the  body,  the  skeleton,  because  the  bones  are  the  levers 
by  means  of  which  move- 
ments are  made.  Each 
muscle  is  usually  attached 
at  two  points.  The  point 
which  is  less  movable,  or 
which  is  nearest  the  center  of  the  body, 
is  called  the  origin,  and  the  other  the 
insertion.  At  the  end  of  each  muscle, 
a  continuation  of  the  connective  tissue 
sheath  is  joined  to  the  periosteum, 
thereby  attaching  the  muscle  to  the 
bone.  In  this  way  nearly  every  mus- 
cle passes  over  a  joint  and  is  attached 
to  two  separate  bones,  thus  making  the 
muscles  an  important  means  of  holding 
the  bones  of  the  skeleton  together. 

The      connective      tissue      does      not   THE  FOOT  is  SHOWN  USED  AS  A 
,  . .         .      .  .  .          LEVER.    ILLUSTRATE  THE  PRIN- 

always  pass  directly  from  the  muscle      CIPLE  BY  USING  YOUR  OWN  FOOT. 


into  the  periosteum.     Sometimes  the 
tissue  forming   the   sheath    unites    at 

one  or  both  ends  to  form  a  white  cord-like  structure  called 
a  tendon,  by  means  of  which  it  is  attached  to  the  bone.  Some 
muscles  have  tendons  at  each  end,  some  at  the  point  of  in- 
sertion only,  and  still  others  have  none  at  all. 

Sometimes  the  point  of  insertion,  or  the  place  where  the  tendon 
is  attached  to  the  bone,  is  at  some  distance  from  the  muscle  itself. 
If  all  the  muscles  necessary  to  give  to  the  hand  its  strength  and 


170  KEEPING  THE  BODY  IN  HEALTH 

variety  of  movement  were  attached  directly  to  the  bones  of  the 
hand,  it  would  be  very  heavy  and  clumsy.  The  hand  is  moved 
by  muscles  in  the  arm,  to  which  it  is  attached  by  long,  slender 
tendons.  When  the  hand  is  opened  and  closed,  the  tendons 
which  attach  the  fingers  to  the  arm  muscles  may  be  seen  in  the 
wrist,  and  the  movements  in  the  muscles  in  the  arm  may  be 
distinctly  felt. 

It  is  of  more  importance  to  us  to  know  how  muscles  act  and 
what  the  relation  of  their  action  is  to  the  work  and  needs  of  life 
How  than  to  know  the  particular  names  that  have  been 

muscles  given  to  them  or  to  the  bones  to  which  they  are 
act  attached. 

When  the  cells  of  a  muscle  contract,  trie  whole  muscle  is  short- 
ened. In  shortening,  each  fiber  thickens,  so  that  there  is  no 

change  in  the  actual  size  of  the 
muscle  but  only  in  its  form. 
The  shortening  of  the  muscle 
causes  it  to  pull  upon  the  bone 
to  which  it  is  attached,  and  this 
results  in  the  bending  of  the 
joint  over  which  the  muscle 
passes,  and  a  movement  of  some 
part  of  the  body.  You  can 

THE  FOREARM  IS  SHOWN  USED  AS  A  LEVER.      easjly     ggg     ^jg     fQr     VOUrSelf     bv 

ILLUSTRATE   THE    PRINCIPLE   BY  USING  *  J  J 

YOUR  OWN  ARM.  CAN  YOU  FEEL  THE  placing  your  hand  upon  the 

large  biceps  muscle  in  the  upper 

arm-  and  noticing  the  shortening  and  thickening  of  the 
muscle  by  means  of  which  the  arm  is  bent  at  the  elbow. 

The  muscles  can  by  their  contraction  only  pull  on  the  bones. 
The  biceps  muscle  can  pull  up  the  forearm,  but  it  cannot  push 
it  back  into  place.  The  forearm  has  to  be  pulled  back  by  another 
muscle.  If  you  bend  your  arm  at  the  elbow  and  place  your  hand 


THE   BODY  IN   MOTION  171 

upon  the  back  of  the  upper  arm  while  you  straighten  it  out  again, 
you  will  feel  the  tightening  of  the  triceps,  the  muscle  which 
pulls  down  the  forearm  and  holds  it  in  place. 

A  great  many  of  the  voluntary  muscles  are  arranged  in  pairs 
of  antagonistic  muscles,  working  against  each  other  in  the  way 
the  biceps  and  triceps  do.  Antagonistic  muscles,  with  their 
steadying  pull,  one  against  the  other,  act  as  brakes  which  keep 
the  movements  from  being  jerky  and  spasmodic,  as  they  other- 
wise would  be.  Most  of  the  bodily  movements,  as  those  of  the 
arms  and  legs,  or  even  the  simple  act  of  standing  erect,  require 
the  action  of  many  muscles,  each  of  which  is  balanced  by  some 
other  one. 

If  a  muscle  is  cut,  it  will  immediately  shorten  like  a  piece  of 
rubber   released   from   a   stretched   condition.     The   muscle   is 
always  more  or  less  stretched  or  taut  when  it  is  alive  Keeping 
and  healthy.     This  tension  in  the  muscle  is  what  is  muscle 
called  muscle  tone.     The  muscle  tone  is  kept  up  by  a  tone 
stream  of  energy  pouring  into  it  from  the  nerve  centers.     When 
one  is  tired  out,  this  energy  is  exhausted,  the  muscles  lose  their 
tone,  and  there  is  a  relaxed  condition.     That  is  why  a  person 
who  is  tired  or  weak  lets  his  head  droop  and  his  chest  collapse. 
When  one  goes  to  sleep  in  a  sitting  position,  the  head  ''nods"  or 
drops  forward,  because  the  muscles  that  hold  it  in  position  be- 
come relaxed. 

We  can  feel  and  see  the  contraction  of  a  working  muscle,  but 
there  is  another  important  change  taking  place  in  it  that  we  can 
neither  see  nor  feel.  As  the  muscle  begins  to  contract,  its  arteries 
dilate  and  fill  with  blood,  for  it  is  the  blood  that  brings  to  the 
muscle  the  energy  that  it  requires  for  work.  A  working  muscle  is 
warmer  than  one  at  rest,  for  the  reason  that  muscular  contraction 
is  always  accompanied  by  the  burning  up  of  some  of  the  food  ma- 
terial which  is  stored  in  the  muscle  and  brought  to  it  in  the  blood. 


172  KEEPING  THE  BODY  IN  HEALTH 

When  any  large  group  of  muscles,  for  instance  those  in  the 
legs,  are  set  in  active  operation,  as  in  jumping  or  running,  one 
very  quickly  gets  out  of  breath.  This  is  due  to  the  fact  that 
when  the  muscle  is  at  work  it  throws  into  the  blood  which  passes 
through  it  a  large  quantity  of  carbonic  acid  gas,  which  is  poison 
to  the  body  and  must  be  hastened  out  through  the  lungs.  The 
greater  the  amount  of  this  gas  thrown  into  the  blood,  the  quicker 
one  becomes  out  of  breath  and  the  more  rapid  the  breathing 
movements  become.  At  such  times  the  lungs  are  expanded 
to  their  utmost  capacity.  Why? 

If  the  exercise  is  less  violent,  but  continued  for  a  longer  time, 
one  may  not  get  out  of  breath,  but  after  a  while  the  muscles 
The  effect  will  become  wearied,  so  that  movement  is  difficult 
of  fatigue  and  may  even  become  impossible.  This  fatigue,  or 
exhaustion,  is  due,  not  to  the  using  up  of  the  muscle's  store 
of  energy,  but  to  the  formation  of  those  poisonous  substances 
that  result  from  the  muscle  work,  which  we  have  already 
studied,  and  which  have  a  harmful  effect  upon  the  muscle. 

The  muscle  is  a  machine  which  may  be  compared  to  a  loco- 
motive, since  it  carries  its  own  fuel.  This  fuel  is  stored  up  in 
the  muscle  in  the  form  of  glycogen,  or  animal  starch,  which 
when  needed  is  converted  into  sugar.  In  work,  the  sugar  is  con- 
verted into  carbon  dioxide  and  lactic  acid.  These  products  are 
muscle  poisons.  As  work  continues,  the  amount  of  oxygen  and 
glycogen  stored  up  in  the  muscle  is  lessened  and  the  poisons 
accumulate.  This  hinders  the  muscle  in  its  work.  It  is  in 
the  situation  of  a  locomotive  whose  fire  is  choked  with  ashes 
while  its  fuel  is  low.  This  is  real  fatigue. 

Exertion  may  be  carried  to  such  a  point  that  death  may  re- 
sult from  the  fatigue  induced.  Runners  have  sometimes  dropped 
dead  at  the  end  of  a  long  course.  Horses  have  been  known  to 
die  suddenly  from  the  same  cause,  and  dogs  also  have  died 


THE  BODY  IN  MOTION  173 

when  attempting  to  keep  up  with  a  bicycle  or  automobile.  Carrier 
pigeons  not  infrequently,  fall  to  the  ground  dead  from  exhaustion 
after  a  long  and  rapid  flight.  In  such  cases,  death  is  due  to  the 
rapid  accumulation  of  the  poisons  formed  by  too  prolonged  ac- 
tion of  the  muscles. 

It  is  interesting  to  notice  that  exercising  a  part  of  the  body 
may  cause  the  whole  body  to  become  fatigued.  For  example, 
one's  arms  may  become  tired  as  the  result  of  running.  How 
can  the  poisons  formed  in  the  leg  muscles  get  to  the  arm  muscles  ? 

Every  movement  of  a  muscle  is  made  in  response  to  an  impulse 
which  it  receives  from  the  nerves.  From  the  brain  or  the 
spinal  cord  a  nerve  goes  to  every  voluntary  muscle  in  the  body. 
Prolonged  muscular  work  wearies  the  brain  and  nerves  as  well 
as  the  muscles,  partly  by  reason  of  the  fatigue  poisons  circulating 
in  the  blood.  One  is  likely  to  become  fatigued  easily  when  per- 
forming exercise  to  which  he  is  not  accustomed.  Why? 

If  one  who  is  fatigued  will  rest  for  a  time,  the  feeling  will  prob- 
ably   disappear.     Rest   generally  cures    fatigue   and   puts  the 
muscles    in    trim   for   work    again.     Rest  gives   the  Curing 
muscles    opportunity    for   increasing   their    store   of  fatigue 
oxygen  and  glycogen  and  also  for  the  washing  out  by  the  lymph 
and  blood  of  the  poison  with  which  they  have  been  filled  by 
work. 

A  very  short  hot  bath  will  lessen  fatigue,  because  it  will 
stimulate  the  circulation  of  the  blood  and  in  that  way  hasten 
the  removal  of  the  fatigue  poisons.  A  prolonged  hot  bath  will 
aggravate  the  feeling  of  fatigue,  and  it  may  even  produce  a 
feeling  of  exhaustion.  Why?  A  short  cold  bath  will  also 
relieve  fatigue  through  its  general  stimulating  effect  upon  the 
body.  One  may  fortify  himself  against  fatigue  by  cold  bathing, 
by  providing  the  muscles  with  an  abundant  supply  of  muscle 
starch  or  glycogen  and  by  deep  breathing  of  pure  cool  air. 


174  KEEPING  THE  BODY   IN  HEALTH 

After  prolonged  and  violent  exercise,  especially  exercise  to 
which  one  has  not  been  accustomed,  one  may  find  himself 
After  suffering  from  muscular  soreness  and  stiffness,  to- 

effects  of  gether  with  a  feeling  of  great  lassitude.  These  feel- 
fatigue  mgs  jo  noj-  usuaiiy  appear  until  some  hours,  perhaps 
a  day  or  even  longer,  after  the  exercise  producing  them.  This 
is  called  secondary  fatigue. 

The  fatigue  caused  by  a  short  period  of  exercise  is  soon 
overcome  and  may  disappear  within  a  few  minutes.  The 
longer  and  the  harder  the  work  performed,  the  longer  the  period 
of  rest  required.  The  soreness  and  stiffness  which  accompany 
secondary  fatigue  usually  disappear  in  a  few  days.  Unless  the 
exercise  has  been  exceedingly  violent  so  that  the  parts  used 
have  been  strained  or  injured  in  some  other  way,  the  muscles 
will  after  a  few  days  become  stronger  than  before  the  practice 
and  able  to  endure  more  work.  The  same  exercise  may  then 
be  repeated  without  bad  effect.  The  soreness  and  stiffness  which 
follow  the  first  attempts  with  any  new  form  of  exercise  should 
not  discourage  one.  They  should  be  regarded  as  an  indication 
that  Nature  is  preparing  the  muscles  for  better  service  by 
strengthening  the  muscular  fibers  and  storing  up  a  larger  amount 
of  energy. 

HEALTH  PROBLEMS 

1.  Which  of  the  actions  of  your  body  occur  without  your  control? 

2.  Take  a  piece  of  lean  meat  which  has  been   thoroughly  boiled   and 
separate  it  into  muscle  fibers.     Be  careful  that  you  do  not  stop  with  bundles 
of  fibers. 

3.  See  if  you  can  trace  two  or  three  muscles  in  your  own  body  from 
origin  to  insertion. 

4.  Why  did  Nature  make  tendons  ?    Why  did  she  not  fasten  the  muscles 
directly  to  the  bone  which  she  wanted  to  move  by  them? 

5.  Suppose  the  triceps  in  the  right  arm  to  be  cut.    How  would  the 
arm  behave?    Explain. 


THE  BODY  IN  MOTION  175 

6.  Try  closing  your  fist  as  tight  as  you  can  and  then  opening  it  quickly, 
repeating  these  movements  with  great  rapidity  as  long  as  you  can.    De- 
scribe your  experience.     If  you  should  reach  a  point  where  you  could  not 
close  the  fist  longer,  explain  why  this  would  happen. 

7.  Describe  some  experience  of  yours  which  has  made  your  muscles 
stiff  the  day  afterward.     Explain. 

8.  Write  an  essay  on  keeping  the  muscles  in  good  working  condition. 

REVIEW  QUESTIONS 

1.  Mention  some  of  the  various  movements  which  we  can  execute  and 
which  require  the  use  of  the  muscles. 

2.  What  are    the    voluntary    muscles?     The    involuntary   muscles? 
Why  are  they  so  called  ? 

3.  How  many  pairs  of  voluntary  muscles  are  there  in  the  human  body  ? 
How  numerous  are  the  involuntary  muscles? 

4.  What  do  the  involuntary  muscles  do  for  the  body  to  keep  it  in 
health? 

5.  Are   the   involuntary  muscles   more   faithful   than   the  voluntary 
muscles  ?    Why  ? 

6.  Tell  something  of  the  different  shapes  and  sizes  of  muscles. 

7.  Describe  a  muscle  fiber.    How  are  the  muscle  fibers  arranged  in  the 
muscles  ? 

8.  What  part  of  meat  is  usually  composed  of  muscle  fibers? 

9.  How  are  the  muscles  attached  to  bones?    What  are  the  names  of 
the  points  where  the  muscles  connect  with  the  bones? 

10.   Describe  a  tendon  and  explain  its  uses. 

IT.   What  happens  when  the  cells  of  a  muscle  contract? 

12.  Tell  how  the  muscles  move  the  bones. 

13.  Where  is  the  biceps  muscle ?     Where  is  the  triceps  muscle? 

14.  Why  are  the  muscles  arranged  in  pairs  working  against  each  other? 

15.  What  will  happen  to  a  muscle  when  it  is  cut? 

1 6.  What  should  we  do  to  keep  up  muscle  tone? 

17.  Explain  why  a  person  who  is  tired  lets  his  head  droop  and  his  chest 
collapse. 

18.  What  change  in  the  character  of  the  blood  takes  place  in  a  muscle 
when  it  contracts  ?    What  is  the  purpose  of  this  change  ? 

19.  Why  does  one  get  out  of  breath  when  he  is  running? 


176  KEEPING  THE  BODY  IN  HEALTH 

20.  What  does  it  mean  to  become  fatigued?    Does  one  become  fatigued 
because  his  muscles  wear  out  or  from  some  other  cause?     May  overwork 
of  one  muscle  fatigue  the  whole  body?    Explain. 

21.  What  may  happen  to  a  person  if  he  exerts  himself  until  he  is  com- 
pletely exhausted? 

22.  What  is  the  best  way  to  relieve  fatigue?    What  is  the  value  of  hot 
and  cold  baths  in  relieving  fatigue? 

23.  What  causes  secondary  fatigue? 


CHAPTER  XIII 

HEALTH  AND  SYMMETRY 

ONE'S  daily  work  usually  provides  much  opportunity  for 
healthful  exercise.  For  girls,  general  housework  —  sweeping, 
dusting,  making  beds — -gives 
splendid  exercise,  bringing  into 
play  the  whole  muscular  system. 
For  boys,  no  general  exercise 
excels  that  which  may  be  secured 
in  " doing  chores"  about  the 
house.  Splitting  and  carrying 
wood,  running  errands,  mowing 
the  lawn,  weeding  the  garden,  if 
done  heartily,  give  good  exercise 
for  all  parts  of  the  body. 

Working  in  the  open  air  is 
much  more  beneficial  than  work- 
ing indoors.  In  cultivating 
flowers,  vegetables,  and  small 
Using  one's  fruits,  —  digging,  hoe- 
daily  tasks  ing,  pruning,  —  one  is 
for  muscle  at  the  same  time  cul- 
tivating health  and 
muscular  development.  The  an- 
cient Greek  boxers  practiced  digging  as  a  means  of  developing 
their  arm  muscles. 

177 


SWEEPING  is  A  FINE  EXERCISE  FOR  DE- 
VELOPING THE  ARM  MUSCLES. 


178  KEEPING  THE  BODY  IN  HEALTH 

In  order  to  be  of  the  greatest  benefit,  exercise  should  be 
enjoyable.  We  know  that  appetite  is  necessary  to  good  diges- 
tion. In  the  same  way,  exercise  that  is  taken  without  relish, 
merely  as  one  takes  a  dose  of  medicine  for  the  sake  of  health, 
will  not  do  us  so  much  good  as  that  which  is  connected  with  some 
interesting  work  or  pleasure  that  makes  it  a  delight. 

Outdoor  games  and  sports  are  among  the  best  forms  of  exercise 

because  they  give  at  the  same  time  fresh  air  and  enjoyment. 

The  exercises  that  are  most  beneficial  to  the  body  in  a 

The  best       general  way  are  those  that  bring  into  play  the  large 

exercise1       muscles  'of  the  body,  especially  those  of  the  legs,  as  in 

running,  swimming,  hill  climbing,  and  rapid  walking. 

Walking,  in  these  days  of  steam  cars,  street  cars,  automobiles, 
telephones,  and  the  like  is  becoming  a  negligible  exercise.  The 
city  youth  who  wishes  to  go  a  few  blocks  usually  jumps  on  the 
trolley  car.  The  country  boy  " hitches  up"  or  takes  the  Ford 
every  time  he  has  to. go  a  mile.  But  in  gaining  a  little  time, 
how  much  physical  benefit  may  be  lost !  Some  one  has  sug- 
gested that  if  a  magical  physician  were  "to  invent  an  elixir  that 
imparted  a  tenth  part  of  the  virtue  of  a  day's  walk  in  the 
open  air,  he  would  be  the  Crcesus  of  pill  makers.  How  much 
would  we  give  for  a  bottle  of  his  concoction !  Yet  we  may 
walk  for  nothing,  and  we  may  begin  to-day." 

Do  you  know  that  when  walking  at  the  rate  of  four  miles  an 
hour  you  breathe  five  times  as  much  air  as  when  you  are  sitting 
still  ?  What  effect  do  you  think  this  has  upon  the  development 
of  your  chest  ?  The  natives  of  Hindustan,  when  they  see  a  man 
going  out  for  a  walk,  say,  "He  goes  forth  eating  air.'"  "If,"  says 
one  authority  on  health,  "every  boy  in  the  United  States  would 
take  daily  one  thousand  slow,  very  deep  breaths  from  now  on 
throughout  his  life,  it  would  almost  double  our  vigor  and  effec- 
tiveness as  a  nation." 


HEALTH  AND   SYMMETRY 


179 


Robert  Burdette  gave   this  advice  to  a  young  man:    "Live 
out  of  doors  all  you  can,  my  boy.     Walk  a  heap.     The  open  air, 


EDWARD  PAYSON  WESTON  WHEN  IN  HIS  SEVENTY-SECOND  YEAR  WALKED  FROM  SAN  FRAN- 
CISCO TO  NEW  YORK. 

the  free  air,  and  the  sunshine  are  as  good  as  the  exercise  — 
better." 


i8o  KEEPING  THE  BODY  IN  HEALTH 

The  man  who  has  done  much,  by  a  remarkable  example, 
to  encourage  walking  is  Edward  Payson  Weston.  When  he 
A  twelve  was  twenty-nine  years  old  he  created  a  sensation  by 
hundred  walking  from  Portland,  Maine,  to  Chicago,  Illinois, 
mile  walk  Forty-three  years  later,  he  walked  from  San  Francisco 
to  New  York,  celebrating  his  seventy-second  birthday,  on  the 
way,  by  walking  seventy-two  miles. 

Do  you  think  Weston  could  have  performed  this  feat  that 
attracted  the  attention  of  the  whole  country  if  he  had  neglected 
personal  hygiene  and  regular  physical  exercise  ?  His  performance 
is  especially  remarkable  as  showing  that  a  man  of  over  three  score 
and  ten  years  may,  after  more  than  forty  years  of  temperate 
living  and  rational  exercise,  be  able  to  endure  the  same  physi- 
cal exertion  that  he  could  before  he  was  thirty.  Weston  him- 
self expressed  the  hope  that  his  trip  "  would  serve  to  show  the 
young  people  of  America  what  right  living  will  do  for  one.'7 
Mr.  Weston  uses  neither  tobacco  nor  alcohol. 

Mr.  Weston  stated  to  the  writer  that  he  never  eats  meat  when 
he  is  taking  a  long  walk,  but  confines  himself  to  the  simplest  and 
most  digestible  foods,  living  almost  wholly  upon  cereals,  milk, 
and  fruits. 

It  is  interesting  to  calculate  the  amount  of  work  one  per- 
forms in  different  kinds  of  exercise.  In  walking,  for  example,  the 
amount  of  work  done  is  much  larger  than  would  be 
the  amount  supposed.  An  eminent  physiologist  has  demonstrated 
of  work  that  in  walking  at  the  rate  of  three  miles  an  hour, 
done  in  one  uses  the  same  amount  of  energy  that  would  be  re- 
quired to  lift  his  body  vertically  through  one  thirteenth 
the  distance  that  he  walks.  That  is,  to  walk  thirteen  feet  requires 
as  much  energy  as  to  lift  one's  self  one  foot.  If  a  boy  weighs  100 
pounds  he  would  use  up  100  foot  pounds  of  energy  in  walking 
thirteen  feet.  It  has  been  estimated  that  the  amount  of  muscular 


HEALTH  AND  SYMMETRY 


181 


work  needed  daily  in  order  to  keep  one  in  health  is  about  150 
foot  tons. 

It  is  evident  that  a  very  fat  person  will  accomplish  a  larger 
amount  of  work  in  traveling  a  given  distance  than  a  thin  person, 
because  he  carries  so  much  dead  weight.  The  man  who  weighs 
twice  as  much  as  he  should  practically  carries  another  man  on 
his  shoulders.  This  renders  walking  much  more  difficult. 

In  going  upstairs  one  is  obliged  to  lift  the  body  through  the 
distance  from  the  lower  floor  to  the  upper.  If  the  distance  were 
ten  feet,  and  the  weight  of  the  person  170  pounds,  this  ascent 
would  involve  an  amount  of  work  equivalent  to  the  lifting  of 
1700  pounds  one  foot  into  the  air.  You  can  calculate  from  your 
own  weight  and  the  distance  between  the  upper  and  lower  floors 
in  your  house  the  amount  of  work  involved  in  lifting  your  body 
from  the  lower  to  the  upper  floor,  and 
how  many  times  it  would  have  to 
be  done  to  accomplish  the  necessary 
amount  of  daily  exercise,  if  it  were  all 
to  be  taken  in  this  way. 

When  one's  daily  work  does  not  in- 
volve the  necessary  amount  of  exercise, 

Takin  an<^  ^  cann°t  ^e  taken  out  of 

exercise  doors,  it  may  be  easily  taken 
in  one's  in  one's  room  if  desired,  in 
such  exercises,  for  example, 
as  standing  erect  and  alternately  raising 
and  lowering  the  heels ;  bending  and  ex- 
tending the  knees ;  supporting  the  body  „ 

J       THIS    EXERCISE    IS    VALUABLE  FOR 

upon  the  hands  between  two  chairs  or 
other  supports,  and  letting  the  body 
down  as  low  as  possible  and  then  raising  it  to  position  —  the  so- 
called  "  dipping  movement"  in  which  the  arms  do  the  work. 


THE     DEVELOPMENT     OF     POISE 
AND   AN   ERECT   POSTURE. 


182  KEEPING  THE  BODY  IN  HEALTH 

A  person  practicing  heel  raising  at  the  rate  of  100  movements 
a  minute  for  twenty-four  minutes,  rising  two  inches  each  time, 
would  do  as  much  work  as  in  walking  a  mile.  How  long  would  a 
man  weighing  150  pounds  have  to  continue  this  exercise  to  do 
the  muscular  work  of  150  foot  tons? 

Some  people  take  a  long  walk  now  and  then;  others  crowd 
the  chief  part  of  their  year's  exercise  into  a  few  weeks'  holi- 
The  best  day  m  ^ne  summer-  Of  course  this  is  much  better 
time  to  than  none  at  all,  but  the  body  needs  its  daily  por- 
exercise  |-jon  of  exercise  as  much  as  it  needs  its  daily  portion 
of  food.  In  fact,  exercise  is  necessary  in  order  for  food  to  be 
properly  assimilated.  It  would  be  about  as  sensible  to  under- 
take to  do  a  month's  eating  in  a  single  day  as  to  take  all  one's 
exercise  for  a  month  on  a  monthly  holiday. 

Exercise  regularly,  if  possible  at  the  same  hour  each  day.  The 
body  will  then  form  the  habit  of  exercise  and  will  unconsciously 
brace  itself  for  the  work  expected.  Between  ten  and  twelve  in 
the  forenoon  is  the  best  time  to  exercise,  and  the  next  best  time 
is  between  four  and  six  in  the  afternoon.  Immediately  after  one 
rises  in  the  morning  is,  however,  a  good  and  convenient  time  for 
most  healthy  persons. 

Much  greater  benefit  is  derived  from  moderate  exercise  many 
times  repeated  than  from  violent  exercises  repeated  a  few  times. 
How  One  not  accustomed  to  exercise  vigorously  should 

fatigue  begin  with  light  exercise,  always  stopping  short  of  ex- 
affects  the  treme  fatigue  and  increasing  the  amount  of  muscular 
work  from  day  to  day.  The  lifting  of  heavy  weights 
or  the  performing  of  other  work  too  heavy  for  the  muscles  may 
permanently  injure  them. 

In  order  to  study  the  effects  of  fatigue  on  the  muscle,  experi- 
ments have  been  made  with  muscles  taken  from  frogs,  which 
retain  their  vitality  for  some  time  after  being  removed  from 


HEALTH  AND  SYMMETRY  183 

the  animal.  When  such  a  muscle  is  stimulated  by  electricity,  it  is 
found  that  its  contraction  and  relaxation  gradually  become  slower. 
There  is  an  increase  of  power  during  the  first  ten  or  twelve  con- 
tractions, but  after  that  the  muscle  becomes  weaker  and  weaker 
until  it  cannot  be  made  to  contract  at  all.  If  left  to  itself  the 

exhausted  muscle  will  recover  in  an  hour  or  so.     But  if  the 

• 

muscle  is  washed  with  pure  blood  or  with  a  salt  solution,  it  will! 
recover  immediately.  If  the  blood  of  a  dog  fatigued  by  exces- 
sive exercise  is  injected  into  the  veins  of  a  fresh  dog,  the  latter 
at  once  shows  signs  of  fatigue.  Explain  why  the  exercise  of  a 
part  of  the  body  will  fatigue  the  whole  body. 

An  exercise  to  which  a  person  is  not  accustomed  is  generally 
more  fatiguing  than  one  to  which  he  is  accustomed,  though  the 
latter  may  involve  much  more  actual  work.  The  amount  of 
'  fatigue  is  more  nearly  proportioned  to  the  difficulty  of  the  work 
than  to  the  amount  done.  For  instance,  suppose  a  person  is  made 
to  walk  on  a  straight  line.  In  one  way,  it  is  little  more  labor  to 
carry  the  body  on  a  line  or  on  a  flat  fence  top  than  it  is  to  walk 
on  the  sidewalk.  Yet  if  you  try  the  experiment  by  walking,  for 
instance,  upon  a  train  track  rail  for  half  a  mile,  you  will  find 
it  much  more  tiresome  than  walking  upon  a  broad  path,  where 
no  effort  is  required  to  keep  the  balance.  Why  is  this?  It  is 
because  one's  nervous  energy  is  used  up  in  maintaining  balance. 

Most  employments  that  are  not  sedentary  give  a  sufficient 
amount  of  exercise  to  maintain  health.  Some  employments, 
however,  give  undue  exercise  to  special  muscles,  and  . 

this  may  lead  to  deformities.     A  carpenter  or  a  black-  for  sym_ 
smith   may   generally   be   distinguished   from   other  metrical 
workers  by  the  way  in  which  he  carries  his  arms.     The  devel°P- 
strongly  developed  flexor  muscles  overbalance  the  ex- 
tensors (point  out  these  muscles)  so  that  the  arms  are  constantly 
bent  when  they  are  at  rest  as  well  as  when  they  are  at  work. 


184 


KEEPING  THE  BODY  IN  HEALTH 


A  BLACKSMITH'S  FLEXOR  MUSCLES  ARE  USUALLY  SO  MUCH  BETTER  DEVELOPED  THAN  HIS 
EXTENSOR  MUSCLES  THAT  HIS  ARMS  ARE  CONSTANTLY  BENT  EVEN  WHEN  HE  IS  AT 
REST. 


Ignorance,  carelessness,  or  weariness  often  lead  a  person  to 
assume  awkward  and  unhealthful  postures  while  he  is  engaged 
in  work,  and  this  habit  may  result  in  fixed  deformities.  It  is,  of 
course,  of  great  importance  to  maintain  a  correct  poise  during 
work. 

It  is  also  necessary  to  give  a  little  thought  to  the  matter  so 
as  to  prevent  a  one-sided  development.  Most  persons  use  the 
muscles  of  the  right  side  much  more  than  those  of  the  left.  Nearly 
all  manual  work  requiring  strength  or  dexterity  is  done  with  the 
right  hand.  Even  the  right  leg  usually  has  enough  more  training 
than  the  left  to  make  it  a  little  larger.  The  extra  work  done  by 
the  right  side  of  the  body  increases  the  strength  of  the  muscles 


HEALTH  AND  SYMMETRY 


of  this  side,  causing  the  spine  to  curve  toward  the  left  side,  and 
the  right  shoulder  to  drop  a  little.  Probably  three  persons  out  of 
four  have  this  deformity  in  some  degree, 
but  with  proper  physical  training  it 
may  be  avoided  or  overcome. 

Even  those  engaged  in  muscular 
work  require  special  exercise  as  a  rule 
to  bring  into  play  the  rest  of  the  muscles 
of  the  body  and  secure  symmetrical  de- 
velopment. A  man  might  sit  down  by 
the  roadside  and  spend  ten  hours  a  day 
breaking  stones  with  a  hammer,  as  men 
may  be  seen  doing  on  the  roadways  of 
England,  and  the  active  exercise  would 
give  him  a  good  appetite,  sound  di- 
gestion, and  strong  arm  muscles ;  but 
the  rest  of  the  body,  if  neglected, 
would  become  seriously  deformed.  His 
limbs  would  become  stiff,  his  gait 
feeble  and  awkward,  and  all  symmetry 
of  form  and  grace  of  movement  would 
be  lost. 

An  important  point  to  remember  is  that  a  little  exercise  taken 
in  the  right  position  will   help    to  counteract    long-continued 
exercise  in  the  wrong  position;  because  in  the  one  Corrective 
case  we  are  working  with  Nature  and  in  the  other  exercises 
against  her.     For  this  reason  a  little  general  exercise  of  the  whole 
body,  taken  in  a  correct  posture,  will  have  the  effect  of  preventing 
deformities  that  might  otherwise  be  caused  by  one's  work.     It  is 
a  good  thing,  however,  to  give  special  exercise  to  those  muscles 
that  have  been  too  long  stretched  or  contracted. 

One  whose  back  has  been  bent  at  his  work  may  save  himself 


PROBABLY  WITH  THREE  OUT  OF 
EVERY  FOUR  PERSONS  THE 
RIGHT  SHOULDER  IS  AT  LEAST 

A    LITTLE    LOWER    THAN     THE 
LEFT.      WHY    IS    THIS    SO? 


i86 


KEEPING  THE  BODY  IN  HEALTH 


from  round  shoulders  and  a  backward  curvature  of  the  spine 
by  spending  five  or  ten  minutes,  several  times  during  the  day, 
in  vigorous  exercise  of  the  back  and  arm  muscles  with  the  spinal 
column  in  the  erect  position.  The  chest  muscles  which  have 

been  inactive   should  also  be  spe- 
cially exercised. 

A  good  way  to  correct  round 
shoulders  and  a  flat  chest  is  to  raise 
the  chest  as  high  as  possible,  draw- 
ing in  slowly  a  long,  deep  breath, 
and  at  the  same  time  pressing  the 
back  of  the  neck  hard  against  the 
collar.  Do  this  repeatedly.  It  will 
bring  the  spinal  column  into  the  cor- 
rect position,  straighten  out  the  back 
between  the  shoulders,  and  deepen 
the  chest.  Persons  who  have  round 
shoulders  and  flat  chests  should 
sleep  on  a  hard  mattress,  with  a 
very  thin  pillow  or  none  at  all. 

When  the  head  is  constantly  bent 
forward  in  studying  or  working,  the 
muscles  at  the  back  of  the  neck  that 
support  the  head  lose  their  tone  from 
being  continually  in  a  stretched 
position,  as  a  piece  of  elastic  over- 
stretched loses  the  power  to  contract.  Unless  the  muscle  tone  is 
restored  by  suitable  exercise,  the  droop  of  the  head  may  become 
permanent.  A  splendid  exercise  for  the  muscles  of  the  back 
is  to  lie  upon  the  floor  face  downward,  and  then  move  the 
head  up  and  down,  raising  the  head  upward  as  far  as  pos- 
sible. Any  other  exercise  that  draws  the  head  upward  and 


A  GOOD  EXERCISE  TO  CORRECT 
ROUND  SHOULDERS  AND  A  FLAT 
CHEST  IS  TO  RAISE  THE  CHEST  AS 
HIGH  AS  POSSIBLE,  DRAWING  IN 
SLOWLY  A  LONG,  DEEP  BREATH, 
AT  THE  SAME  TIME  PRESSING 
THE  BACK  OF  THE  NECK  HARD 
AGAINST  THE  COLLAR. 


HEALTH  AND   SYMMETRY 


187 


backward  will  help  to  strengthen  the  muscles  that  hold  the 
head  erect. 

The  strength  of  the  abdominal  muscles,  the  elasticity  of  which, 
as  we  have  seen,  has  such  an  important  relation  to  the  health  of 
the  body,  may  be 
greatly  increased 
by  the  following 
simple  exercises: 
walking  on  tiptoe 
with  the  chest  held 
high;  running 
around  the  room  on 
all  fours ;  lying  on 
the  back,  with  the 
legs  held  straight, 
raising  them  to  the 
perpendicular,  re- 
peating ten  to 
twenty  times  three 
times  a  day;  lying 
on  the  back  and 
raising  the  body  to 
the  sitting  position 
with  the  hands 
placed  at  the  back 
of  the  neck. 

One  whose  work  keeps  his  hands  bent  continually,  as  in  row- 
ing, shoveling,  or  writing,  may  counteract  the  effects  of  this  by 
forcibly  extending  the  fingers  as  much  as  possible  several  times 
in  succession,  at  intervals  during  his  work.  The  feet  also,  be- 
cause they  are  so  constantly  restricted  by  shoes,  should  be  given 
stretching  and  contracting  exercises  to  prevent  weak  arches. 


THE  ABDOMINAL  MUSCLES  SHOULD  ALWAYS  BE  KEPT  IN 
GOOD  TONE,  FOR  THEY  HAVE  AN  IMPORTANT  EFFECT 
UPON  THE  HEALTH  OF  THE  BODY.  THE  EXERCISE  SHOWN 
IN  THE  PICTURE  IS  GOOD.  THE  LEGS  SHOULD  BE  RAISED 
AND  LOWERED. 


l88  KEEPING  THE  BODY  IN  HEALTH 

HEALTH  PROBLEMS 

1.  How  far  do  you  walk  in  going  to  school?     Is  the  road  level  or  does 
it  go  up  and  down  hill?    About  how  many  times  should  you  have  to  walk 
this  distance  in  order  to  do  150  foot  tons  of  work? 

2.  Suppose  two  men  equally  tall,  one  weighing  270  pounds  and  the 
other  175  pounds,  walk  a  mile  together.     Which  has  done  more  work  at 
the  end  of  the  mile ?    Why? 

3.  In  running  a  long-distance  race,  athletes  do  not  start  out  at  the 
height  of  their  speed,  but  run  only  moderately  fast  at  first.    Why  do  they 
do  this? 

4.  Perhaps  you  know  persons  whose  arm  muscles  are  strong  and  well- 
developed,  but  who  cannot  handle  a  pen  or  a  needle  easily.     What  is  the 
reason  for  this?    What  muscles  does  a  blacksmith  train?    A  writer?    A 
needleworker? 

5.  Observe  how  many  of  your  classmates  have  one  shoulder  higher 
than  the  other.    What  is  the  cause  of  this  ?    How  may  it  be  remedied  ? 

REVIEW  QUESTIONS 

1.  What  is  necessary  in  order  that  exercise  may  be  of  the  greatest 
benefit? 

2.  What  kinds  of  work  can  a  girl  do  that  will  give  her  much  healthful 
exercise  ?    What  kinds  can  a  boy  do  ? 

3.  What  sports  afford  the  best  exercise? 

4.  Why  is  walking  so  beneficial  an  exercise  ? 

5.  Tell  about  the  achievements  of  Edward  Payson  Weston. 

6.  How  much  daily  exercise  is  needed  in  order  to  keep  one  in  health? 

7.  Describe  some  good  general  exercises  which  may  be  taken  in  one's 
room. 

8.  Is  it  well  for  a  person  to  crowd  all  his  exercise  for  the  year  into  a  few 
weeks  in  the  summer?    Why? 

9.  What  is  the  best  time  for  taking  exercise  ? 

10.  What  is  the  effect  of  tight  clothing  upon  one  who  wears  them  while 
exercising  or  at  any  time  ? 

11.  Why  is  very  violent  exercise  repeated  a  few  times  not  so  beneficial 
as  moderate  exercise  repeated  many  times  ? 

12.  What  effect  does  fatigue  have  on  the  muscles? 


HEALTH  AND   SYMMETRY  189 

13.  Why  does  exercise  of  a  part  of  the  body  fatigue  the  whole  body? 

14.  What  is  the  effect  of  overexertion  upon  the  muscles? 

15.  Why  is  work  to  which  a  person  is  not  accustomed  more  fatiguing 
than  work  to  which  he  is  used,  although  the  latter  may  require  more  muscular 
effort  ? 

1 6.  Explain  how  certain  kinds  of  work  cause  a  one-sided  development 
of  the  body. 

17.  Describe  an  exercise  which  will  correct  round  shoulders. 

18.  Describe  an  exercise  which  will  strengthen  the  abdominal  muscles. 

19.  How  may  one  whose  work  keeps  his  fingers  bent  prevent  them  from 
becoming  crooked? 

20.  Why  do  the  feet  need  special  exercise? 


Nerve  Cell 


CHAPTER  XIV 

FEELING  AND  THINKING 

IF  a  community  of  people  are  to  live  and  work  harmoniously 
together,  they  must  have  some  kind  of  government.  The  body 

community  must  also  have  its 
government.  The  ruler  of  the 
body  is  the  mind  working 
through  the  nervous  system. 

It  is  in  response  to  commands 
sent  out  through  the  nervous 
system  that  the  digestive  organs 
begin  to  work  when  food  is 
eaten ;  that  the  lungs  and  heart 
work  faster  to  increase  the 
breathing  when  we  run,  so  that 
a  greater  amount  of  oxygen  may 
be  carried  to  the  muscles ;  and 
that  the  skin  pours  out  perspira- 
tion to  cool  off  the  body.  The 
nervous  system  brings  all  the 
cells  and  organs  into  communi- 
cation, causing  them  to  work 
together  for  the  common  good. 

There  are  two  forms  of  nerve 
tissue :  nerve  cells  and  nerve  fibers. 

HERE  is  A  DIAGRAM  OF  A  NERVE  CELL  AND  ITS  The  nerve  fibers  are  feally  addj_ 

BRANCHES.      NOTE  THAT  THE  LONG  NERVE 

FIBER  IS  REALLY  A  PART  OF  THE  CELL.  tionS    tO     tllC    Cells,      Or     partS      Of 

I90 


JVeuri/emma  or 
Nucleated  Sheath 


FEELING  AND  THINKING 


IQI 


them.     Most  nerve  cells  send  out  two  or  three  slender  arms, 

one  or  more  of  which  may  be  prolonged  into  nerve  fibers ;  and 

others  connect  with  the  branches  of  other  cells  or  end  in  the 

spaces  between  the  cells.     A  nerve 

cell  with  its  branches  is  called  a 

neuron.    A  careful  examination  of 

the  branches  shows  that  they  are 

covered  with  minute  buds.     It  is 

supposed  that  these  buds  are  for 

the    purpose    of    communicating 

directly  or  indirectly  with  other 

cells. 

The  nerve  cells  are  usually  found 
in  groups,  and  each  group  has  its 
own  particular  work  to  do  in  the 
government  of  the  body.  A  group 
of  nerve  cells  having  some  special 
work  is  called  a  nerve  center  or 
ganglion. 

The  little  bundles  of  nerve  fibers 
which  pass  out  from  a  nerve  center 
unite  to  form  larger  bundles,  which 
pass  to  the  different  parts .  of  the 
body.  When  the  body  of  an  ani- 
mal is  dissected,  white,  glistening 
cords  are  found  running  every- 
where among  the  tissues.  These 
bundles  of  nerve  fibers  are  called 
nerves  or  nerve  trunks. 

There  are  two  divisions  of  the  nervous  system,  just  as  there 
are  two  of  the  muscular  system.  All  the  involuntary  muscles, 
those  not  under  the  control  of  the  will,  are  governed  by  what 


YOU  SEE  HOW  THE  MIND  W°RKING 

THROUGH  THE  BRAIN,  SPINAL  CORD, 
AND  NERVES  CAN  CONTROL  ALL  PARTS 
OF  THE  BODY? 


KEEPING  THE  BODY  IN  HEALTH 


is  called  the  sympathetic  nervous  system.    The  voluntary  muscles 
are  controlled  by  the  central  nervous  system. 

The  brain  and  the  spinal  cord  are  the  great  centers  of  the 
nervous   system.     In  the  brain  lies  the  power  by  which  we  feel, 

think,  and  will.  The  brain  is  simply 
an  assemblage  of  nerve  cells  or 
neurons,  hundreds  of  millions  of 
them.  With  the  exception  of  the 
whale  and  the  elephant,  the  brain 
of  man  is  larger  than  that  of  any 
other  animal. 

The  spinal  cord  enters  the  cranium 
(the  skull)  and  connects  with  the 
brain  through  a  large  opening  at  the 
base  of  the  skull.  The  cord  is  a 
soft  white  substance,  about  the 
thickness  of  a  pencil.  It  passes 
through  the  canal  of  the  backbone, 
which  forms  a  protection  for  it.  It 
is  also  protected  by  membranes  as 
is  the  brain. 

The  brain  and  the  spinal  cord 
send  out  nerves  to  the  different  parts 
of  the  body,  forty-three  pairs  in  all. 
Twelve  of  these  arise  from  the  under  side  of  the  brain  and  are 
called  cranial  nerves.  They  pass  through  small  openings  in  the 
base  of  the  skull  and  are  distributed  to  the  face,  the  organs  of 
sense,  —  eye,  ear,  nose,  and  mouth,  —  and  to  the  organs  of  the 
chest  and  abdomen.  Thirty-one  pairs  of  spinal  nerves  pass 
out  from  the  spinal  cord  through  openings  in  the  sides  of  the 
spinal  canal.  The  spinal  nerves  are  distributed  to  the  trunk 
and  the  extremities  of  the  body. 


THE  BRAIN,  THE  SPINAL  CORD,  AND 
THE  ROOTS  OF  SPINAL  NERVES  ARE 
HERE  SHOWN. 


FEELING  AND  THINKING 


193 


White  Matter 
(Nerve  Fibres) 


Gray  Matter 
Tfierre  Cet/sJ 


The  nerves  are  for  the  purpose  of  carrying  messages  between 
the  different  parts  of  the  body  and  the  spinal  cord  and  brain. 
The  cell  branches,  as  well  as  the  matter  composing  How  we 
the  center  of  the  cell,  consist  of  transparent  jellylike  feel  and 
matter  as  clear  as  water,  yet  possessing  the  most  won-  think 
derful     properties     of 
any  known  substance. 
By  means  of  these  liv- 
ing threads,  which  are 
many    times     smaller 
than  the  finest  spider 
web,    the    nerve    cells 
of  the  different  parts 
of  the  body  are  in  con- 
stant    communication 
with  one  another,  just 
as  various  points  and 
cities  of  a  country  are 
in   communication   by 

means  of  telegraph  and  telephone  wires.  The  brain  is  the 
central  office  which  connects  all  the  different  parts.  If  the  skin, 
bones,  blood  vessels,  and  muscles  were  removed,  and  nerve  fibers 

and  cells  only  were 
left,  the  outline  of  the 
body  would  still  be 
complete.  The  feeling 
organs  of  the  brain, 
the  nerves,  really  oc- 
cupy the  whole  body, 
just  as  do  the  cir- 
culating organs,  the 
blood  vessels. 


THIS   DIAGRAM    SHOWS   THE    STRUCTURE   OF  THE   SPINAL 
CORD  AND  THE  ORIGIN  OF  THE  SPINAL  NERVES. 


•Posterior  Poot 


^Anterior  Root 


HERE  is  A  VIEW  OF  A  SECTION  OF  THE  SPINAL  CORD  AND 

A  SPINAL  NERVE, 


194  KEEPING  THE  BODY  IN  HEALTH 

Experiments  upon  animals  have  shown  that  if  a  nerve  going 
to  any  part  is  cut,  the  application  of  electricity  to  the  outer  por- 
tion of  the  nerve  will  cause  the  muscle  to  contract  but  will  not 
cause  any  feeling;  while  if  electricity  is  applied  to  the  inner 
portion  there  will  be  no  muscular  contraction,  but  a  feeling  of 
pain.  This  experiment  shows  that  nerve  trunks  are  made  up 
of  two  kinds  of  nerve  fibers,  one  carrying  impressions  inward 
to  the  brain,  and  the  other  carrying  impulses  or  commands  out- 
ward to  the  muscles,  or  other  organs. 

The  nerve  fibers  which  carry  impressions  or  sensations  in- 
wards are  called  sensory  nerves,  while  those  which  carry  com- 
Ingoine  mands  or  impulses  outwards  and  cause  all  the  differ- 
andout  ent  motions  of  the  body,  are  called  motor  nerves. 
going  jn  the  spinal  nerves,  the  sensory  and  the  motor  fibers 

are  generally  bound  together  in  the  same  bundle. 
Most  of  the  cranial  nerves  are  composed  exclusively  of  either 
sensory  or  motor  fibers. 

Think  of  the  different  kinds  of  sensations  that  you  experience 
and  see  how  many  you  can  enumerate.  Besides  the  special 
senses,  —  hearing,  seeing,  smelling,  tasting,  and  feeling,  —  we 
have  what  are  called  general  sensations,  such  as  fatigue,  hunger, 
thirst.  You  will  see  that  the  sensory  nerves  are  of  many  different 
kinds.  For  each  kind  of  sensation,  there  is  in  the  brain  a  special 
group  of  cells  or  a  nerve  center  having  charge  of  that  particular 
sense,  as  you  can  see  in  the  picture  (p.  191). 

The  motor  nerves,  or  nerves  of  work,  are  also  connected  with 
different  groups  of  cells  in  the  brain,  each  of  which  has  charge 
of  some  particular  organ  or  class  of  organs.  The  muscles,  the 
stomach,  the  liver,  the  kidneys,  and  all  other  important  organs 
have  each  their  controlling  centers. 

It  is  not  easy  to  comprehend  the  exact  manner  in  which  im- 
pressions are  carried  by  the  nerves.  The  best  way,  perhaps,  is 


FEELING  AND  THINKING 


195 


to  compare  the  process  roughly  to  the  action  which  passes  along 
a  row  of  bricks  set  on  end  in  such  a  way  that  when  a  brick  falls 
over  it  will  strike  the  one  next  to  it,  which  in  turn  will  fall  against 
the  next,  and  so  on  to  the  end  of  the  line.  No  matter  how  great 
the  length  of  the  line,  the  impulse  given  to  the  first  brick  will  be 
sent  through  all  the  bricks  to  the  last. 
If  we  imagine  the  line  of  bricks  to  be  a 
nerve  fiber,  with  one  end  in  the  skin  and 
the  other  connected  with  a  cell  in  the 
brain,  we  may  get  some  idea  of  how  an 
impression  may  be  conducted  along  a 
nerve. 

The  large  mass  of  nerve  tissue  which 
fills  the  upper  part  of  the  skull  is  called 
The  cere-  ^he  cerebrum.  It  makes  up 
brum  and  three  fourths  of  the  entire 
its  work  brain  and  is  sometimes  called 
the  large  brain,  to  distinguish  it  from  the 
cerebellum,  which  is  sometimes  called  the 
small  brain. 

The  cerebrum  is  divided  into  two 
hemispheres,  the  right  and  the  left.  The 
surface  presents  many  furrows  and  folds, 
or  convolutions.  The  outside  is  covered 
with  layers  of  nerve  cells,  which  give  it  a 
gray  color.  It  is  this  gray  material  of  the 
brain  with  which  one's  mental  processes 
are  chiefly  associated.  Underneath  the 
gray  matter  the  brain  is  white  in  appearance  and  is  composed 
of  the  nerve  fibers  which  connect  with  the  cells.  A  network  of 
fibers  connects  the  different  parts  of  the  cerebrum,  and  count- 
less fibers  pass  into  the  spinal  cord. 


EVERY  ORGAN  is  UNDER  THE 

CONTROL  OF   THE  NERVOUS 
SYSTEM. 


KEEPING  THE  BODY  IN  HEALTH 


The  cerebrum  is  used  in  all  our  tnmking.  Through  the  nerve 
messages  which  come  to  it  from  all  parts  of  the  body,  it  receives 
the  sensations  of  light,  heat,  sound,  smell,  taste,  and  others. 
It  also  sends  out  the  messages  that  cause  voluntary  movement. 
Every  part  of  the  muscular  system  is  connected  with  the  brain ; 

and  each  group  of  muscles 
has  a  corresponding  group 
of  cells  by  which  it  is  con- 
trolled 

When  the  cerebrum  is 
removed  from  the  head  of 
an  animal,  it  does  not  die 
at  once,  but  a  remarkable 
change  takes  place  in  it. 
If  it  is  a  frog,  it  will  swim 
when  placed  in  water,  and 
hop  when  pinched  or  stimu- 
lated in  any  way.  In  this 
respect  it  appears  like  any 
other  frog.  But  it  evidently 
has  no  intelligence.  It  is,  in 
fact,  quite  idiotic.  If  made 
to  hop,  it  will  hop  into  the 

NOTICE    THIS    OUTLINE    OF    THE  UPPER  SURFACE       -  _..,  , 

OF  THE  CEREBRUM.   NOTE  THAT  IT  is  DIVIDED  fare  as  readily  as  anywhere. 
INTO  TWO  HEMISPHERES,  THE  RIGHT  AND  THE   jf  ieft  alone,  it  will  remain 

LEFT.  .  .       . 

without  stirring  until  it  per- 
ishes. It  has  no  power  to  issue  commands  to  itself.  It  can 
perform  only  those  reflex  actions  which  require  no  intelligence' 
but  which  are  the  response  to  some  outside  stimulus.  Why  can 
it  perform  such  acts  but  not  those  requiring  intelligence? 

Disease  of  this  part  of  the  brain  in  human  beings  weakens 
the  intelligence.  It  has  been  observed  that  the  larger  the  cere- 


FEELING  AND  THINKING 


197 


•Front 


Rear 


Cerebrum 


brum  in  proportion  to  the  rest  of  the  brain,  the  greater  the  in- 
telligence of  the  animal.  It  is  proportionately  much  larger  in 
man  than  in  any  other  animal. 

Beneath  the  back  part  of  the  cerebrum  is  the  cerebellum,  or 
little  brain.     It  is  similar  in  form  to  the  cerebrum,  and  like  it 
is  divided  into  a  right  and  a  left  half.    It  is  also  covered  The  cere_ 
with  a  layer  of  nerve  cells.  bellum 

When   the   cerebellum  is  removed  from  birds   or  and  its 
animals,    they    lose    the   power   to   make    regulated 
movements.     A    man    whose    cerebellum    is    injured    staggers 
about    as    though    in- 
toxicated.    The  move- 
ments   are    jerky   and 
overdone.      A    person 
who  is  intoxicated  can- 
not walk  steadily,  be- 
cause of  the  paralyzing 
effect     which     alcohol 
has  upon  his  cerebel- 
lum.    So  it  seems  that 
the  chief  office  of  the 
cerebellum  is  to  regu- 
late and  coordinate  the 
movements  of  the  muscles,  and  to  maintain  the  balance  of  the 
body  by  causing  the  muscles  to  act  in  harmony. 

The  medulla  is  an  expansion  of  the  upper  end  of  the  spinal 
cord.     It  contains  many  nerve  fibers  which  connect  the  higher 
parts  of  the  brain  with  the  spinal  cord  and  the  body.  The 
It  is  a  center  for  reflex  and  automatic  actions,  espe-  medulla 
daily  for  those  which  are  of  the  greatest  importance  and  its 
to  the  body,  such  as  the  beating  of  the  heart  and 
the  breathing. 


Cerebe/lum 


Varo/ii 


•Medu//a  Ob/onyota 


THIS  SIDE  VIEW  (RIGHT)  OF  THE  BRAIN  SHOWS  THE  CERE- 
BRUM, CEREBELLUM,  AND  MEDULLA  OBLONGATA.  THE 
CEREBRUM  AND  CEREBELLUM  ARE  COVERED  WITH  A 
LAYER  OF  NERVE  CELLS. 


work 


ig8  KEEPING  THE  BODY  IN  HEALTH 

We  have  seen  that  life  may  continue  although  the  cerebrum 
or  cerebellum  are  injured  or  even  removed.  But  the  mere 
puncture  of  the  medulla  with  a  needle  is  sufficient  to  cause 
death,  because  it  stops  the  breathing.  For  this  reason  the 
medulla  has  been  called  the  "  vital  knot." 

When  the  hand  comes  in  contact  with  a  hot  object,  it  is 
instantly  drawn  away.  One  does  not  have  to  say  to  himself, 
Reflex  "My  hand  is  likely  to  be  burned,  so  I  had  better  draw 
action  ft  away."  The  hand  is  pulled  away  before  there  has 
been  time  for  thought.  In  a  little  baby  with  no  power  to  reason 
the  hand  would  instantly  be  pulled  away  from  a  candle  flame. 

li  ToJ3r-a/n 

t 


WHEN  A  CHILD'S  HAND  TOUCHES  A  LIGHTED  CANDLE  THE  INCARRYING  OR  SENSORY  NERVES 
CONVEY  THE  IMPRESSION  INSTANTLY  TO  THE  SPINAL  CORD,  AND  THE  OUTCARRYING  OR  MOTOR 
NERVES  INSTANTLY  CONVEY  AN  IMPULSE  TO  THE  MUSCLES  OF  THE  ARM  TO  WITHDRAW  THE 
HAND.  THIS  IS  REFLEX  ACTION. 

When  a  sensation  gives  rise  to  motion  in  this  way,  the  action  is 
called  reflex.  Reflex  actions  are  of  immense  importance  in  pro- 
tecting the  body  from  injuries  of  various  sorts.  The  acts  of 
winking,  swallowing,  sneezing,  coughing,  and  vomiting  are  all 
reflex.  These  are  helpful  acts ;  and  the  impulse  to  perform  them 
may  be  so  violent  that  it  cannot  be  suppressed  by  the  will. 
Sneezing,  for  example,  is  for  the  purpose  of  discharging  some 


FEELING  AND  THINKING  199 

offending  object  from  the  nose ;  coughing  for  removing  some 
object  from  the  air  passages;  vomiting  to  empty  the  stomach 
of  something  that  needs  to  be  expelled.  The  closing  of  the  eye- 
lid when  the  eye  is  touched  is  another  example  of  reflex  action. 
The  internal  organs  are  controlled  almost  entirely  by  such 
action 

The  work  of  the  spinal  cord  is  the  same  as  that  of  the  medulla. 
It  is  the  passage  through  which  impulses  are  conducted  to  and 
from  the  brain.  It  is  also  the  center  for  reflex  actions.  The  spinal 
When  the  spinal  cord  is  cut  across  or  severely  injured,  cord  and 
all  parts  of  the  body  below  the  injury  are  paralyzed,  its  work 
and  lose  their  feeling,  because  they  have  lost  their  connection  with 
the  cerebrum,  the  seat  of  feeling  and  of  action.  But  reflex  actions 
are  still  possible.  For  instance,  a  hot  iron  applied  to  the  foot 
will  produce  no  pain,  even  though  the  foot  may  be  severely 
burned.  But  if  the  sole  of  the  foot  is  tickled,  it  will  be  jerked 
away  by  a  strong  contraction  of  the  muscles,  although  the  per- 
son may  not  even  know  that  his  foot  has  moved.  The  feet  of  a 
person  who  is  sound  asleep  will  move  in  the  same  manner  when 
tickled.  This  shows  clearly  that  the  spinal  cord  without  the 
aid  of  the  brain  can  carry  on  reflex  actions  for  those  parts  of  the 
body  that  are  reached  by  the  spinal  nerves.  For  this  reason 
a  frog  without  a  head  may  be  made  to  hop,  or  a  headless  turtle 
to  walk  about.  These  acts  are  governed  by  the  spinal  cord. 

Besides  these  natural  reflex  actions  requiring  no  intelligence, 
there  are  what  are  called  acquired  reflexes.  Take  the  act  of 
walking,  for  example.  When  a  child  first  attempts  to 
walk,  a  voluntary  effort  is  required  each  time  the  foot 
is  moved  and  put  forward.  After  a  while  he  can 
walk  a  long  distance  without  thinking  about  it  or  giving  any 
attention  to  the  feet.  The  mind  may  be  wholly  occupied  with 
something  else.  The  action  has  then  become  reflex;  it  is 


200  KEEPING  THE  BODY  IN  HEALTH 

performed  without  any  effort  of  the  mind.  This  is  true  only 
when  one  walks  at  his  usual  pace.  If  you  try  to  walk  much 
slower  or  much  faster  than  usual,  you  will  find  that  you  have  to 
make  a  conscious  effort  to  do  so. 

Writing  is  at  first  a  laborious  act  which  requires  very  close 
and  constant  effort  to  direct  the  muscles  employed.  But  the 
accomplished  penman  is  able  to  write  rapidly  without  seeming 
to  give  any  thought  to  the  formation  of  the  letters.  He  thinks 
of  the  word  he  wishes  to  write  and  his  hand  produces  it.  In 
swimming,  bicycle  riding,  and  many  other  performances,  the 
necessary  movements  are  made  without  thought,  after  the  nerves 
involved  in  them  have  been  trained  by  practice.  Without  this 
provision  it  would  not  be  possible  to  become  very  skillful  in 
any  art  or  trade. 

At  the  base  of  the  large  brain  or  cerebrum  are  some  very 
interesting  groups  of  cells  which  serve  as  middlemen.  They 
receive  orders  from  the  large  brain  and  transmit  them  through 
the  spinal  cord  to  the  organs  for  which  they  are  intended.  The 
control  of  those  acts  which  are  performed  very  frequently  is  for 
the  most  part  transferred  from  the  cerebrum  to  these  centers. 
They  may  be  called  the  servants  of  the  cerebrum,  since  they  are 
always  ready  to  carry  out  its  orders  and  at  last  become  so  well 
trained  that  they  can  do  some  kinds  of  work  without  super- 
vision of  the  higher  centers.  In  this  way  the  cerebrum  is  relieved 
from  much  labor  and  drudgery  and  left  free  for  higher  kinds  of 
work. 

Each  time  an  act  is  repeated  it  is  done  with  a  little  greater  ease. 
After  a  time  it  is  done  without  any  effort  of  the  mind.  Then 
How  it  has  become  a  habit.  "Sow  an  act  and  reap  a 

habits  are  habit;  sow  a  habit  and  reap  a  character."  Every 
formed  acf-  of  importance  not  only  originates  in  the  brain, 
but  makes  an  impression  upon  it.  It  is  in  this  way  that  our 


FEELING  AND  THINKING  2OI 

characters  are  built.  The  character  is  largely  formed  by  our 
habits.  Perhaps  we  may  say  that  our  character  is  the  sum  of 
all  our  habits,  and  our  habits  are  formed  by  constantly  repeated 
actions. 

One  of  the  most  wonderful  of  the  abilities  of  the  mind  is  mem- 
ory.    How  are  sight  pictures  and  sound  pictures  stored  in  the 
mind,  and  how  are  we  able  to  recall  them?     In  some  How  we 
way  impressions  made  through  the  eye,  the  ear,  and  remember 
the  other  senses  cause  such  actions  and  changes  in  the  nerve  cells 
that  they  are  able  under  the  right  sort  of  conditions  to  call  back 
the  impressions  they  have  received. 

In  order  for  a  thing  to  be  remembered  it  is  necessary  that 
the  first  impression  shall  be  clear  and  strong.  Whether  an  im- 
pression lasts  or  not  depends  mainly  upon  how  clear  it  is.  For 
this  it  is  necessary  that  the  attention  should  be  concentrated  while 
the  thing  is  being  learned.  Good  attention  is  the  first  essential 
of  a  good  memory.  The  more  active  the  mind  is  in  regard  to 
any  impression  when  it  is  being  made,  the  longer  the  impression 
is  likely  to  be  retained. 

Exercise  is  quite  as  necessary  for  the  health  of  the  brain  and 
the  nerves  as  for  the  rest  of  the  body.  Mental  strength  and 
capacity  are  developed  by  mental  work,  just  as  the  muscles  are 
developed  by  muscular  work.  So,  too  the  brain  may  be  injured 
by  overstudy,  just  as  the  muscles  may  be  hurt  by  overstrain. 

When  the  brain  is  weary,  impressions  made  upon  it  are  slight 
and  soon  become  indistinct.  For  this  reason  it  is  better  to 
spend  only  two  or  three  hours  at  a  time  in  hard  study.  A  short 
period  of  exercise.,  especially  if  taken  in  the  open  air,  will  refresh 
the  brain  and  make  it  active  and  ready  to  receive  new  impressions. 

Muscular  exercise  is  of  great  benefit  to  brain  workers.  We 
have  seen  how  exercise  keeps  the  stream  of  life  fresh  and  pure 
and  washes  away  the  poisonous  products  that  tend  to  clog  the 


202  KEEPING  THE  BODY  IN  HEALTH 

mental  machinery.  Students  and  professional  men  break  down 
much  more  often  through  neglecting  to  take  muscular  exercise 
than  through  doing  too  much  mental  work. 

Plenty  of  fresh  air  and  good  food  are  needed  for  the  support 
of  the  brain  and  nerves,  just  as  for  the  rest  of  the  body.  Eating 
too  much  or  living  on  unwholesome  or  indigestible  food  clogs 
and  hinders  the  brain  in  its  work.  Clear  thinking  and  a  good 
memory  can  go  on  only  in  a  healthy  and  unclouded  brain.  Over- 
eating and  indigestion  are  especially  likely  to  weaken  the  mem- 
ory and  to  produce  a  state  of  mental  confusion,  lack  of  power  to 
concentrate  the  mind,  and  inability  to  decide  questions. 

An  abundance  of  sound  sleep  is  necessary  for  the  health  of 
the  nervous  system.  During  perfectly  sound  sleep,  the  brain  is 
wholly  inactive ;  the  spaces  about  the  nerve  cells  become  filled 
with  lymph,  and  the  parts  worn  by  use  undergo  repair.  Dur- 
ing the  activity  of  the  day  there  is  little  opportunity  for  the 
repair  of  brain  tissue.  This  work  is  done  almost  wholly  during 
sleep.  At  least  seven  or  eight  hours  of  sleep  are  required  each 
night  by  grown  people.  Young  people  who  are  still  growing 
require  more  than  older  persons. 

During  unsound  sleep  the  brain  is  partly  active  but  in  an 
irregular  way.  Confused  pictures  present  themselves.  The 
result  is  dreaming.  When  one  constantly  dreams  at  night  of 
the  work  he  has  been  doing,  it  is  an  indication  that  those  parts 
of  the  brain  used  during  the  day  are  not  being  properly  rested 
and  restored  at  night.  They  are  in  danger  of  becoming  diseased. 
A  vacation  or  change  of  occupation  is  then  necessary.  Sleep- 
lessness is  often  caused  by  eating  late  in  the  evening.  The  best 
way  to  secure  sound  sleep  is  to  take  only  ripe  fruit  or  other  very 
easily  digested  food  for  the  evening  meal.  Tea,  coffee,  and  choco- 
late tend  to  produce  sleeplessness. 

Fatigue  caused  by  out-of-door  exercise  has  a  good  effect  in 


FEELING  AND  THINKING  203 

bringing  sleep.  A  prolonged  bath,  of  from  fifteen  to  twenty  min- 
utes, at  a  temperature  of  96  to  98  degrees,  taken  just  before 
going  to  bed,  is  an  excellent  remedy  for  sleeplessness. 

Failure  to  eliminate  the  waste  matters  from  the  body  regularly 
is  one  of  the  most  common  causes  of  nervousness  and  sleep- 
lessness. It  is  also  perhaps  the  most  common  of  all  causes  of 
exhaustion  and  chronic  fatigue.  The  poisons  produced  in  the 
colon  by  the  putrefaction  of  food  residues  have  been  shown 
to  be  potent  in  causing  fatigue.  These  poisons,  when  extracted 
from  the  colon  contents  and  applied  to  the  tissues  of  animals, 
were  found  to  produce  all  the  evidences  of  chronic  fatigue.  To 
keep  the  brain  and  nerves  in  a  healthy  condition,  the  colon 
should  be  kept  free  from  putrefying  food  wastes. 

We  have  already  noted  that  alcohol  paralyzes  the  nerve  cells 
that  control  movements,  causing  a  staggering  walk  and  falling. 
Alcohol  also  makes  a  man  temporarily  insane,  by  Nerve 
paralyzing  certain  of  the  nerve  cells  so  that  the  brain  poisons 
is  unable  to  make  correct  judgments.  Peculiar  and  unnatural 
combinations  of  ideas  are  made,  often  with  terrible  results.  A 
man  who  is  naturally  peaceable  may  while  under  the  influence 
of  alcohol  become  violent,  destructive,  and  ferocious.  In  the 
disease  caused  by  alcohol,  called  delirium  tremens,  the  drunk- 
ard's ideas  become  curiously  mixed.  The  sufferer  sees  snakes, 
reptiles,  and  all  sorts  of  monsters  and  strange  shapes  before  him. 

The  ill  effects  of  tobacco  upon  the  nervous  system  have  been 
pointed  out  by  many  eminent  physicians.  Here  are  some  of  the 
things  they  say  about  it : 

"  Giddiness  is  a  common  effect  of  excessive  tobacco  smoking. 
Tremor  is  one  of  the  commonest.  It  may  be  cured  entirely  by 
abandoning  the  use  of  tobacco." 

"  Sleeplessness  is  one  of  the  most  common  effects  of  tobacco 
smoking. " 


204  KEEPING  THE  BODY  IN  HEALTH 

It  has  been  shown  that  tobacco  poison  affects  the  auditory 
nerve  and  so  causes  defective  hearing  or  deafness. 

"The  use  of  cigarettes  has  an  evil  effect  upon  the  mucous 
membrane  lining  of  the  nose  and  throat,  and  as  these  organs  are 
closely  connected  with  the  organ  of  hearing,  anything  that 
affects  them  is  likely  to  react  upon  the  hearing." 

Tobacco  also  affects  the  optic  nerve,  weakening  the  power  of 
color  perception,  and  injuring  the  sight  in  other  ways.  This  is 
recognized  in  every  trade  or  profession  that  requires  quick  and 
accurate  sight. 

A  certain  railway  company  issued  the  following  notice  to 
employees  :  "For  the  betterment  of  the  service  and  the  safety  of  the 
public  it  will  from  this  date  be  the  policy  of  this  company  NOT 
to  retain  in  its  employ  men  who  use  intoxicating  liquors  or 
cigarettes." 

Tobacco  has  also  a  harmful  effect  upon  the  mental  efficiency 
of  young  smokers.  Out  of  2336  cigarette  smokers  who  were 
attending  public  school,  only  six  were  reported  as  "bright 
pupils."  A  very  few  were  "average."  All  the  rest  were 
"poor"  or  "worthless"  pupils. 

Its  effects  upon  the  moral  nature  are  also  marked.  A  physi- 
cian who  has  had  the  best  opportunities  for  seeing  the  effects  of 
tobacco  upon  the  morals  says  he  is  convinced,  from  much  obser- 
vation, that  the  poisonous  gases  from  tobacco  stupefy  the  nerve 
centers  that  control  the  moral  sensibilities,  so  that  the  fine  edge 
of  the  moral  nature  is  blunted  and  the  smoker's  sense  of  the 
difference  between  right  and  wrong  is  blurred. 

HEALTH  PROBLEMS 

i.  Suppose  you  should  cut  a  nerve  leading  to  the  end  of  your  finger 
and  that  you  could  keep  it  from  healing,  what  would  happen  to  your  finger  ? 
Why? 


FEELING  AND  THINKING  205 

2.  Does  nature  take  special  pains  to  keep  the  brain  from  becoming 
injured?    If  you  think  so,  give  reasons. 

3.  Why  does  man,  like  most  other  animals,  have  a  long  spinal  col- 
umn? 

4.  Show  just  how  a  command  gets  from  your  brain  down  to  the  last 
joint  in  your  finger  so  that  you  can  move  it.     How  does  a  command  travel 
down  to  your  big  toe  so  that  you  can  move  it  ? 

5.  Think  of  a  good  way  to  show  that  there  is  a  special  group  of  cells 
in  the  brain  that  has  to  do  with  vision ;   another  group  that  has  to  do  with 
hearing ;  another  group  that  controls  the  right  hand,  and  so  on. 

6.  Mention  a  number  of  reflex  actions  which  are  not  spoken  of  in  the 
text.     Can  you  mention  any  harmful  reflex  actions?    If  so,  how  can  one 
control  them  so  that  they  will  not  get  him  into  trouble  ? 

7.  Mention  at  least  five  habits  that  you  possess  which  are  not  men- 
tioned in  the  text.     Why  is  it  proper  to  speak  of  one's  character  as  "the 
sum  of  his  habits"? 

8.  Can  you  close  your  eyes  and  visualize  clearly  your  father,  mother, 
brothers,  -and  sisters?     Can  you  image  your  breakfast  table  so  that  you 
can  describe  the  dishes,  the  people  who  sat  around  the  table,  and  so  on? 

9.  Can  you  now  hear  the   voices  of  your  father,  mother,  brothers, 
and  sisters  even  though  they  are  absent  ? 

10.  Take  something  you  have  forgotten  in  literature,  arithmetic,  spell- 
ing, or  any  other  subject,  and  see  if  you  can  tell  why  you  have  not  remem- 
bered it.  What  could  you  have  done  so  that  it  would  have  remained  with 
you? 

n.  Have  you  ever  tried  taking  exercise  when  you  could  not  learn  your 
school  lessons  rapidly?  Did  it  clear  your  mind?  Explain. 

12.  What  has  happened  in  the  nervous  system  of  the  person  who  is 
drunk?  Suppose  the  alcohol  remained  in  his  system  permanently,  what 
would  become  of  him  ? 

REVIEW  QUESTIONS 

1.  What  is  the  source  of  the  commands  that  set  the  digestive  organs 
at  work?    That  make  the  lungs  work  faster  when  necessary  ? 

2.  What  are  the  two  kinds  of  nervous  tissue? 

3.  Describe  the  nerve  cell.    Of  what  use  are  the  buds  on  the  branches 
of  nerve  cells? 

4.  What  is  a  nerve  center,  or  ganglion? 


206  KEEPING  THE  BODY  IN  HEALTH 

5.  What  are  the  bundles  of  nerve  fibers  called? 

6.  What  are  the  two  divisions  of  the  nervous§  system  ? 

7.  What  is  the  "headquarters,"  as  one  might  say,  of    the  nervous 
system  ? 

8.  How  does  the  spinal  cord  connect  with   the  brain?    Describe  this 
cord  in  detail,  and  explain  its  relation  to  the  rest  of  the  nervous  system. 

9.  What  are  the  nerves  that  convey  impressions  from  the  senses  to  the 
brain  called  ?    Those  that  carry  commands  from  the  brain  to  the  muscles  ? 

10.  Show  how  impressions  are  conducted  from  the  brain  to  the  muscles. 

11.  What  is  a  reflex  action?     What  is  its  use?    Name  some  reflex  ac- 
tions which  may  occur  during  sleep. 

12.  What  name  is  given  to  the  large  brain?    The  small  brain? 

13.  With  what  is  the  outside  of  the  brain  covered? 

14.  What  part  of  the  brain  do  we  use  in  our  thinking? 

15.  What  happens  to  a  frog  when  its  cerebrum  is  removed?    What 
does  this  show  regarding  the  work  of  the  cerebrum  ? 

16.  When  the  cerebellum  is  removed  from  birds  and  animals,  what 
happens  to  them? 

17.  Where  is  the  medulla  situated  ?    What  work  does  it  have  to  perform  ? 

18.  What  is  the  work  of  the  spinal  cord? 

19.  Why  can  reflex  actions  occur  when  a  person  is  without  conscious- 
ness? 

20.  How  is  it  possible  for  a  frog  without  a  head  to  hop  ? 

21.  How  does  one  form  habits?    What  is  the  relation  between  habits 
and  character  ? 

22.  How  is  it  possible  for  one  to  retain  the  memory  of  any  experience 
he  has  had  ? 

23.  Why  is  it  difficult  to  recall  things  when  one  is  weary? 

24.  How  can  one  cultivate  a  good  memory  ? 

25.  Is  exercise  necessary  for  the  health  of  the  brain  and  nerves? 

26.  Why  should  one  not  study  when  he  is  fatigued?    What  kind  of 
exercise  is  good  for  brain  workers  ?    Why  ? 

27.  What  sorts  of  habits  will  prevent  one's  thinking  clearly? 

28.  Is  sleep  necessary  for  the  health  of  the  nervous  system?    What 
is  a  good  way  to  overcome  sleeplessness  ? 

29.  Why  does  one  dream?    What  kinds  of  habit  will  be  likely  to  make 
one  dream  a  good  deal? 

30.  Mention  some  nerve  poisons  and  their  effect  on  the  brain. 


CHAPTER  XV 


GATEWAYS  OF  .THE  MIND  —  SIGHT 

THE  brain  has  only  one  way  of  getting  information  from  the 
outside  world.  This  is  by  means  of  sensations  received  through 
the  nervous  system.  There  are  two  kinds  of  sensations:  (i) 
Those  which  arise  from  conditions  within  the  body,  such  as  fa- 
tigue, drowsiness,  pain,  hunger,  and  thirst.  These  are  called 
general  sensations.  (2)  Those  which  are  caused  by  some  stimu- 
lus from  outside,  as  sight,  hearing,  smell,  taste,  and  touch,  by 
means  of  which  we  get  a  knowledge  of  objects  in  the  world  about 
us.  These  are  called  the  special  senses.  They  are  the  ave- 
nues or  gateways  to  the  mind.  The  information  brought  to 
the  brain  through  them  is  the  food 
of  the  mind,  or  thought  material. 

Perhaps  the  most  remarkable  of 
these  avenues  to  the  brain  is  the 
eye.  The  eye  is  a  picture-making 
The  eye,  instrument,  very  much  like 
the  body's  a  photographer's  camera, 
camera  orjv  mucn  mOre  wonder- 
fully and  perfectly  made.  The  eye 
of  an  ox  recently  killed  may  be  pre- 
pared in  such  a  way  that  one  can 

clearly  see  the  picture  formed  by  the  lens  of  the  eye  on  the 
dark  curtain  stretched  across  the  back  of  the  eye  globe.  In 
some  mysterious  way,  by  means  of  a  special  nerve,  the  optic 

207 


•rot/'c 


THE  EYE  IS  A  PICTURE -MAKING 
INSTRUMENT,  MUCH  MORE  WON- 
DERFULLY AND  PERFECTLY  MADE 
THAN  THE  PHOTOGRAPHER'S 
CAMERA. 


208 


KEEPING  THE  BODY  IN  HEALTH 


nerve,  which  connects  the  eye  with  the  brain,  a  record  is  made 
of  this  picture  in  the  cells  of  the  brain. 

One  looks  at  an  object,  —  the  face  of  a  friend,  a  beautiful  flower, 
a  strange  animal,  a  collision  of  vehicles  in  the  street.  The  next 
day,  or  it  may  be  years  after,  the  picture  may  be  reproduced  in 
the  mind,  showing  that  a  record  has  been  made  in  the  brain. 
A  famous  artist  once  produced  from  memory  a  copy  of  a  picture 
hanging  in  a  gallery  in  a  distant  city.  The  copy  was  so  like  the 
original  that  it  was  difficult  to  distinguish  one  from  the  other. 
This  reproducing  of  original  impressions  is  what  the  brain  is 

doing  all  the  time  for  every 
one  whose  brain  and  eyes 
and  optic  nerves  are 
healthy. 

The  eyes  are  well  pro- 
tected by  nature.     They 
are  set  in  deep  bony  sock- 
ets in  the  skull,  open  in 
front.     At  the  back  part 
there  is  an  open-  Thepro_ 
ing     through  tectionof 
which  pass  the  the  eye 
nerves  which  connect  the 
eye  with  the  brain.     The 
eye  socket  is   lined  with 
fat,   which  forms    a    soft 
cushion    for   the   eye    to 
rest   and    turn  on,    and    helps    to   protect    it   from   injury. 

The  eyelids,  eyelashes,  and  eyebrows  also  assist  in  protecting 
the  eyes  from  injury.  The  eyelids  protect  the  eye  from  too 
much  light  and,  by  quickly  closing  and  covering  the  exposed 
part  of  the  eyeball,  they  shield  it  from  any  threatening  blow. 


THE  LACHRYMAL  GLAND  PRODUCES  A  SECRETION 
WHICH  MOISTENS  THE  EYE.  WHEN  THIS  SECRE- 
TION IS  PRODUCED  IN  TOO  LARGE  A  QUANTITY 
TO  BE  DRAINED  OFF  THROUGH  THE  LITTLE 
CANALS  PROVIDED  FOR  THE  PURPOSE,  IT  FLOWS 
OVER  THE  EYELIDS  IN  TEARS. 


GATEWAYS  OF  THE   MIND  —  SIGHT 


209 


2.  e  vat  or  Pa/f>  etir, 
Superior  OM<jue 
Superior /fee/us 
Jnternat. 


Along  the  edge  of  the  eyelids  may  be  seen  the  openings  of 
numerous  little  glands  which  pour  out  an  oily  substance  that 
prevents  the  ordinary  moisture  of  the  eye  from  overflowing. 
The  eyelashes,  with  which  the  edges  of  the  lids  are  also  fur- 
nished, keep  dust  out  of  the  eyes. 

The  little  gland  that  produces  moisture,  the  lachrymal  gland, 
is  within  the  socket  of  the  eye,  at  the  outer  and  upper  side. 
Here  a  secretion  is  constantly  formed  in  small  quantities  for  the 
purpose  of  moistening  the  eyes.  This  secretion  is  drained  away 
by  means  of  two  little  canals,  one  at  the  edge  of  each  lid,  at  the 
inner  corner  of  the  eye.  These  little  canals  open  into  a  small  sac 
from  which  the  tears  are 
carried  into  the  nose, 
through  a  duct  called  the 
nasal  duct.  When  the 
secretion  from  the  lachry- 
mal gland  is  formed  in 
too  great  quantity  to  be 
carried  off  in  this  way, 
the  tears  flow  over  the 
lids  and  run  down  the 
cheeks. 

Each  eye  is  provided  with  six  little  muscles.     One  end  of  each 
of  these  is  attached  to  the  socket  and  the  other  to  the  eyeball. 
By  this  means   the   eye   may  be  turned  in  various  Theparts 
directions.      Think  what    would    be   the  effect  if  it  of  the  eye 
were  not  possible  to  move  the  eyeball !  and  their 

The  eyeball  has  three  layers  or  coats:  the  outer 
coat,  or  sclerotic;  the  middle  coat,  or  choroid;  the  inner  coat,  or 
retina.   The  sclerotic  is  formed  of  a  dense  white  membrane,  —  the 
white  of  the  eye,  as  we  call  it.     In  its  front  part  is  a  trans- 
parent   portion    called    the    cornea,    which     lets    the    light 


Exferno/Rectus 

jnferfor  Rfcfui 

^/nfer/or  OA/ryue 

EACH  EYE  IS  PROVIDED  WITH  SIX  LITTLE  MUSCLES 
BY  MEANS  OF  WHICH  IT  CAN  BE  TURNED  IN  EVERY 
DIRECTION. 


2IO 


KEEPING  THE  BODY  IN  HEALTH 


Poster/ or 
Chombe. 


through  into  the  eye,  just  as  a  window  lets  the  light  into  a 

room. 

Next  to  the  sclerotic  and  in  close  contact  with  it  is  the  choroid, 

which  is  of  a  rich,  purple  color.     In  the  front  of  the  choroid,  just 

at  the  back  of  the  transparent  cornea,  is  the  iris,  a  movable,  mus- 

cular curtain  lined  with 
dark  pigment.  The  iris 
is  the  colored  part  of  the 
eye,  blue,  brown,  gray, 
or  black,  which  we  see 
through  the  transparent 
cornea.  It  has  an  open- 
ing in  the  center  called 
the  pupil. 

The  iris  regulates  the 
amount  of  light  that  enters 
the  eye.  When  the  light 
is  dim,  the  opening  is  en- 

^&&  tO  let  ^  aS  mUCh 
light  aS  pOSSlble.  When 

the   light   is   strong,    the 

pupil  is  made  very  small  to  protect  the  eye.  You  have  seen  the 
pupils  in  the  eyes  of  a  cat  in  the  sunlight  reduced  to  mere  slits, 
while  on  the  contrary  the  pupils  in  the  eyes  of  a  cat  that  has  been 
in  the  dark  are  so  enlarged  that  the  iris  can  scarcely  be  seen. 
The  pupils  of  the  eyes  of  cats  and  of  certain  other  animals  can 
be  opened  wider  than  the  pupils  of  human  eyes,  and  for  this 
reason  such  animals  can  see  in  the  dark  better  than  we  can. 

The  retina,  the  inner  coat  of  the  eyeball,  contains  the  nerves 
of  sight.  It  is  formed  by  the  spreading  out  of  the  optic  nerve, 
which  enters  the  eyeball  at  the  back,  nearly  opposite  the  pupil. 
It  is  composed  of  several  layers  of  different  kinds  of  cells,  which 


Sclerotic  Coot 


fiferve  Sheath 


Cana/for 
'Centra/ Artery 


THIS    PICTURES    A    SECTION    OF    THE    EYE    SHOWING 
THE   DIFFERENT   PARTS  AND   CHAMBERS. 


GATEWAYS  OF  THE   MIND  —  SIGHT  211 

are  connected  with  the  ends  of  the  fibers  of  the  optic  nerve.  In 
this  way  it  is  connected  with  the  nerve  centers  in  the  brain  that 
preside  over  the  sense  of  sight.  The  layer  of  cells  next  to  the 
choroid  or  middle  coat  has  a  purple  color.  The  color  fades  when 
the  retina  is  exposed  to  light,  but  is  constantly  reproduced  by 
the  choroid. 

Just  at  the  back  of  the  iris  is  the  crystalline  lens,  which  divides 
the  inside  of  the  eye  into  two  chambers.  The  large  chamber 
at  the  back  of  the  lens,  called  the  posterior  chamber,  forms  the 
greater  part  of  the  cavity  of  the  eyeball.  It  is  filled  by  a  trans- 
parent, jelly  like  substance  called  vitreous  humor.  The  small 
chamber  in  the  front  of  the  lens,  called  the  anterior  chamber,  is 
filled  with  aqueous  humor,  a  watery  fluid  which  runs  out  when 
the  eyeball  is  pierced  with  a  sharp  instrument. 

The  lens,  aided  by  the  convex  surface  of  the  cornea,  forms 
images  of  the  objects  that  we  see.     An  image  formed  by  a  lens 
in  the  front  of  a  camera  may  be  seen  upon  the  ground 
glass  at  the  back  of  the  camera.     If  we  hold  a  con-  the 
vex  lens  before  a  window  and  at  the  proper  distance  forms 
from  a  screen  of   thin  oiled  paper  or  ground  glass,  images  and 
we  may  see  upon  the  screen  a  perfect  picture  of  the 
window,  but  much  smaller  than  the  original.     The 
lens  and  the  cornea  of  the  eye  form  images  upon  the  retina  in 
the  same  way  that  the  image  is  formed  on  the  screen  or  camera. 

Many  colored  fabrics  fade  or  lose  their  color  when  long  ex- 
posed to  the  sun's  rays.  Muslin  may  be  bleached  or  made  white 
by  exposure  to  the  sun.  When  the  retina  taken  from  the  eye 
of  an  animal  is  exposed  to  the  sun,  the  color  is  bleached  out  in 
the  same  way.  But  if  it  is  left  in  contact  with  the  choroid,  and 
is  placed  in  the  dark,  it  will  soon  recover  its  color. 

If  we  allow  the  image  formed  by  a  lens  to  fall  upon  the  retina 
taken  from  the  eye  of  an  animal,  the  picture  will  be  bleached 


212  KEEPING  THE  BODY  IN  HEALTH 

upon  the  retina  by  the  action  of  the  sun's  rays.  This  is  exactly 
what  happens  when  we  see  an  object.  The  lens  of  the  eye, 
assisted  by  the  cornea,  forms  an  image  which  is  bleached  upon 
the  retina  in  the  way  described.  The  impression  made  upon 
the  retina  is  carried  to  the  brain  by  means  of  the  optic  nerve. 

Impressions  made  upon  the  retina  may  last  after  the  object 
making  the  impression  is  removed.  A  thing  may  be  looked  at 
for  only  the  hundredth  part  of  a  second,  yet  it  will  take  a  whole 
tenth  of  a  second  for  the  image  formed  to  die  away.  You  can 
see  that  if  a  second  picture  is  presented  before  the  first  has  died 
away,  the  pictures  will  blend.  The  effect  is  then  the  same  as 
if  both  objects  were  seen  at  the  same  time. 

A  toy  has  been  made  to  illustrate  this.  It  consists  of  a  piece 
of  white  card  with  two  strings  upon  which  it  can  be  so  twirled 
that  first  one  side  is  shown,  then  the  other.  On  each  side 
of  the  card  a  different  picture  is  painted.  Suppose,  for  instance, 
that  on  one  side  of  the  card  is  a  lion  and  on  the  other  his  cage. 
When  the  card  is  rapidly  twirled  by  being  blown  upon,  the  lion 
will  be  seen  in  his  cage.  Or  it  may  be  a  horse  on  one  side 

and  his  rider  on  the 
other.  Twirling  the 
card  rapidly  will  have 
the  effect  of  seating  the 
rider  upon  his  horse. 
Explain  the  principle. 

THIS     DIAGRAM     SHOWS     HOW     REVERSED     IMAGES     ARE  Jf  VOU 

FORMED  UPON  THE   RETINA   OF    THE    EYE.       WHY   IS    IT  * 

THAT   WE   DO   NOT   SEE   THINGS   UPSIDE   DOWN?  fully    the 

by  a  lens  you  will  see 

that  the  picture  is  inverted.  The  two  sides  are  also  reversed. 
This  is  because  the  rays  of  light  cross  each  other  in  passing 
through  a  lens.  Why  is  it  that  though  the  picture  in  the  eye  is 
upside  down,  yet  we  seem  to  see  the  object  right  side  up? 


GATEWAYS  OF  THE  MIND  — SIGHT 


213 


OBSERVE  CHANGES  IN  THE  LENS  IN 
ACCOMMODATION. 


Do  you  think  a  very  young  infant  sees  things  right  side  up 
as  we  do  ? 

By  experimenting  with  a  lens  held  at  a  certain  distance  from 
a  screen,  you  will  see  that  the  images  of  near  and  of  distant  ob- 
jects are  not  equally  perfect.  In  order  to  get  good  seeing 
pictures  of  all  objects,  you  must  either  change  the  near  and 
position  of  the  lens,  or  use  a  thicker  lens  for  near  ob-  far  obJects 
jects  and  a  thinner  one  for  distant  objects.  The  position  of  the 
lens  in  the  eye  cannot  be  changed.  It  is  fixed  at  a  certain  dis- 
tance from  the  retina.  Neither  can 
it  be  exchanged  for  a  thicker  or 
thinner  one,  according  to  the  ob- 
ject to  be  looked  at.  But  Nature 
has  provided  a  means  by  which 
the  lens  may  be  made  thicker  or 
thinner  and  so  may  adjust  itself 
perfectly  to  see  objects  at  different  distances.  This  is  done  by 
means  of  the  muscular  ring  surrounding  the  lens,  —  the  sus- 
pensory ligament.  This  work  of  adjusting  the  lens  is  called 
accommodation.  The  eye  seems  to  see  without  effort  objects  at 
a  distance,  and  accommodation  is  exercised  only  for  near  ob- 
jects. A  perfectly  natural  eye  cannot  adjust  itself  to  see  objects 
nearer  than  five  to  eight  inches. 

In  reading  or  doing  any  kind  of  close  work,  the  muscles  of  the 
suspensory  ligament  are  contracted  to  thicken  the  lens  and  so 
adjust  it  for  seeing  near  objects.  If  the  work  is  long  continued, 
it  is  a  good  thing  to  relax  these  muscles  and  rest  the  eyes  by 
occasionally  gazing  out  of  a  window  into  the  distance. 

In  some  persons  the  eyeballs  are  long  from  the  front  to  the 
back,  so  that  the  retina  is  farther  than  usual  from  the  TWO  kinds 
lens.     Here  is  a  little  experiment  which  will  help  you  of  sight 
to  understand  what  effect  this  extra  length  has  upon  the  sight. 


214  KEEPING  THE  BODY  IN  HEALTH 

Take  a  lens  which  will  make  upon  a  screen  held  a  few  inches 
behind  it  a  distinct  image  of  distant  objects.  If  the  screen  be 
moved  farther  from  the  lens  the  image  of  the  objects  will 


THE  NORMAL  EYE.   THE  EYEBALL  IS  JUST    THE   NEARSIGHTED  EYE.   THE  EYEBALL 
THE  RIGHT  LENGTH  AND  THE  LENS  HAS      IS  TOO  LONG  SO  THAT  THE  RAYS  OF  LIGHT 
JUST  THE  RIGHT  DEGREE  OF  CURVATURE      FOCUS  IN  FRONT  OF  THE  RETINA. 
SO  THAT  THE  RAYS  OF  LIGHT  ARE  FOCUSED 
PRECISELY  UPON  THE  RETINA. 

become  indistinct.  But  if  the  objects  are  brought  nearer  the 
lens,  a  clear  image  of  them  will  again  be  formed  upon  the  screen. 
This  shows  us  that  if  the  retina  of  an  eye  should  happen  to 
be  farther  from  the  lens  than.it  ought  to  be,  distant  objects 
would  not  be  seen  clearly,  although  near  objects  might  be  seen 
distinctly.  A  person  having  such  eyes  is  said  to  be  near- 
sighted. 

In  other  cases  the  eyeball  is  shorter  than  usual,  so  that  the 
retina  is  brought  too  near  the  lens.  In  these  cases  distant  ob- 
jects may  be  clearly  seen,  while  near  objects  are  blurred  or  in- 
distinct. Such  eyes  are  called  far  sighted. 

If  you  watch  an  elderly  person  trying  to  read  without  glasses, 
you  will  notice  that  usually  the  book  is  held  a  long  way  from  the 
eyes.  The  reason  for  this  is  that  at  about  the  age  of  forty-five 


GATEWAYS  OF  THE  MIND  —  SIGHT 


215 


years  the  lens  begins  to  harden,  so  that 
it  cannot  be  accurately  adjusted  to  near 
objects. 

In  some  cases  the  curvature  of  the 
cornea  is  uneven  and  some  parts  are 
flatter  than  other  parts.  When  this 
irregularity  is  enough  to  distort  the 
image  so  that  objects  are  not  seen  clearly, 
it  is  called  astigmatism.  This  is  a  very 
common  eye  defect  and  is  often  com- 
bined with  nearsightedness  or  farsight- 
edness. 

Nearsighted,  farsighted,  and  most  old 
persons  need  the 
assistance  of  glasses 
which  will  cause  the 
image  to  fall  exactly 
on  the  retina,  so 
that  the  object  may 
be  distinctly  seen. 
For  a  nearsighted 
eye,  on  which  the 


rays  of   light  meet   THE   FARSIGHTED   EYE.     THE 

EYEBALL  IS  TOO  SHORT  AND 
THE  RAYS  OF  LIGHT  FOCUS 
BACK  OF  THE  RETINA. 


THE  DOUBLE  CONCAVE 
LENS.  NOTICE  THAT 
IT  SPREADS  THE  RAYS 
OF  LIGHT  AND  SO  CAN 
BE  USED  TO  CORRECT 
A  NEARSIGHTED  DE- 
FECT AS  SHOWN  IN 
THE  FOLLOWING  IL- 
LUSTRATION. 


before  they  reach 
the  retina,  concave 
lenses  are  needed  to 

spread  the  rays  of  light  farther  apart.     Far- 
sighted  eyes  in  which  the  rays    reach  the 
retina  before  they  meet,  need  con-  Wearing 
vex  lenses,  which  will  bend  the  Slasses 
rays  of  light  toward  each  other,  and  cause 
them  to  meet  more  quickly.     Old  persons 


2l6 


KEEPING  THE  BODY  IN  HEALTH 


need  convex  lenses  which  should  be 
changed  as  age  increases.  When  an  old 
person  finds  himself  obliged  to  pull  his 
glasses  down  on  his  nose  in  order  to  see 
clearly,  it  is  a  sign  that  he  needs  lenses 
that  are  more  convex. 

The  eye  is  the  organ  of  sight,  but  it  is 
with  the  brain  that  we  actually  see.  If  the 
optic  nerve  is  cut,  pictures  will  still  be 
With  what  f°rmed  in  the  eye  but  there  will 
do  we  be  no  sight.  It  is  with  the  brain 
really  see?  fa^t  we  form  judgments  of  the 


LIGHT    WILL    FOCUS    EX- 
ACTLY  ON   THE   RETINA. 


THE  ONLY  WAY  TO  CORRECT 

images   transmitted  through  the   eye,  as       NEARSIGHTEDNESS, 

to  their  distance,  shape,  position,  solidity. 

The  nerve  centers  controlling  sight  have 

to  be   trained   by 

practice  to  form  accurate  judgments. 
A  little  baby  reaches  out  for  everything 
it  sees,  no  matter  how  far  away,  and 
experiments  have  shown  that  not  until 
it  is  several  months  old  does  it  have  a 
definite  idea  of  distance.  Why? 

A  young  Scotchman  who  was  born 
blind  received  his  sight  when  he  was 
thirty  years  old  by  means  of  an  opera- 
tion* He  at  first  thought  that  every- 
thing he  saw  was  quite  close  to  him. 
The  first  day  that  he  sat  near  a  window, 
he  put  out  his  hand  to  touch  the  side- 

He 

said,  "The  first  meal  I  ate  was  an  odd 
experience.  When  I  saw  that  great  hand 


THE     ONLY    WAY    TO     CORRECT 

FARSIGHTEDNESS,  —  USING  A   walk,  which  was  two  stones  below. 

CONVEX  LENS,  SO  AS  TO 
FOCUS  THE  RAYS  OF  LIGHT 
ON  THE  RETINA. 


© 


CARE  OF  THE  EYES 

Only  one  pair  of  eyes  for  life! 


Dangers  at  Home 


The  Right  Way 


AVOID 


i 


Facing  the  light 
Reading  in  the  twilight 
Reading  when  lying  on  the  back 
\  Using  the  "common"  towel 

Dangers  at  School 


AVOID 


Sh  i  ny°5Iackboa  rds 
Fine  print  or  glazed  paper 


\  Non-adjustable  desks' 
.    ^RubBi  n<j5  eyes  with  dirty  fingers 

When  the  eyes  water,  blur  or  ache,  or  the  school 
doctor  reports  defect, consult  an  oculist  Headaches 
indigestion,  and  other  troubles  may  be  due  to 
defective  eyes. 


2i8  KEEPING  THE  BODY  IN  HEALTH 

with  a  huge  fork  approaching  my  mouth,  the  impulse  to  dodge 
was  almost  irresistible."  Explain  this  man's  experience. 

The  eyes  are  such  a  precious  possession  that  they  need  to  be 
guarded  carefully.  Think  from  how  much  one  is  shut  out  who 
The  care  does  not  ^ave  ^e  use  °^  these  wonderful  organs  that 
of  the  reveal  all  the  beautiful  and  interesting  things  in  the 
eyes  world  around  him. 

Carelessness  in  the  use  of  the  eyes  while  one  is  young  may 
cause  a  great  deal  of  trouble  and  even  blindness  later  in  life. 
It  is  important  to  avoid  straining  the  eyes.  This  is  most  likely 
to  occur  in  reading.  When  one  is  interested  in  a  book,  it  is 
sometimes  a  temptation  to  go  on  reading  into  the  twilight. 
Reading  in  a  poor  light  is  a  great  strain  on  the  eyesight. 
Why  ?  Reading  very  fine  print  for  a  long  time  without  resting 
the  eyes  also  strains  them.  Why? 

Reading  on  the  cars  is  likely  to  be  injurious  to  the  eyes,  because 
of  the  shaking  which  continually  changes  the  distance  between 
the  book  and  the  eye.  You  can  see  what  a  tax  this  is  upon  the 
muscles  of  accommodation,  which  must  keep  adjusting  the  eye 
to  the  changed  distance. 

Reading  while  lying  down  is  a  bad  practice.  In  this  position 
too  much  blood  comes  to  the  eyes,  which  are  likely  to  become 
congested.  The  book  is  also  likely  to  be  held  in  an  awkward 
position  in  relation  to  the  eyes. 

It  is  not  a  good  thing  to  read  when  first  awaking  in  the  morning, 
as  it  takes  a  little  while  for  the  eyes  to  become  accustomed  to 
the  light.  Sudden  exposure  of  the  eyes  to  very  bright  light 
may  be  injurious  for  the  same  reason. 

The  direction  in  which  the  light  falls  is  of  very  great  impor- 
tance to  the  eyes  in  such  occupations  as  reading,  writing,  and 
needlework.  The  light  should  shine  upon  the  work,  not  upon 
the  eyes.  You  may  find  out  for  yourself  the  best  position  for 


GATEWAYS  OF  THE  MIND  — SIGHT 


219 


doing  near  work  of  any  kind  by  trying  a  few  experiments.  Sit 
or  stand  with  your  back  to  a  window  while  you  read.  You  will 
see  that  your  shadow  falls  upon  the  page  and  darkens  it. 
Face  the  window,  and  you  will  see  that  this  is  even  more  un- 
satisfactory. The  light  shines  directly  into  the  eyes,  while  the 
book  is  in  shadow.  Sit  with  your  right  side  to  the  window  and 
you  will  find  a  great  improvement.  The  light  now  falls  directly 
upon  the  page  and  not  upon  the  eyes.  But  try  writing  in  this 


IT  IS  OF  THE  GREATEST  IMPORTANCE  TO  HAVE  A  SCHOOLROOM  WELL  LIGHTED,  SO  THAT  THERE 
WILL  NOT  BE  TOO  STRONG  LIGHT  IN  SOME  PARTS  OF  THE  ROOM  AND  TOO  WEAK  LIGHT  IN 
OTHER  PARTS.  THIS  ROOM  IS  EVENLY  LIGHTED  THROUGHOUT. 

position.  The  hand  then  casts  a  shadow  upon  the  paper  which 
will  obscure  the  light  just  where  it  is  most  needed.  Sit  now 
with  your  left  side  to  the  window,  and  you  will  find  that  the  light 
is  just  right  for  all  purposes. 


220  KEEPING  THE  BODY  IN  HEALTH 

Notice  where  the  windows  in  your  schoolroom  are  placed  and 
how  the  light  falls  upon  your  desk.  Is  it  a  good  thing  for  the 
teacher's  desk  to  be  placed  in  front  of  a  window?  Which  is 
the  best  position  for  the  blackboards,  between  the  windows  or 
facing  them  ? 

Severe  headaches,  indigestion,  and  other  nervous  troubles 
may  be  caused  by  defective  eyesight.  People  very  often  think 
their  digestion  is  out  of  order  when  they  really  need  glasses.  If 
the  eyes  become  easily  tired  and  can  be  used  but  a  short  time 


EVERY  SCHOOL  BUILDING  SHOULD  BE  EQUIPPED  WITH  FACILITIES  FOR  THE  MEDICAL  EXAMI- 
NATION OF  PUPILS.  IT  IS  ESPECIALLY  IMPORTANT  THAT  PUPILS  SHOULD  HAVE  THEIR  EYES 
TESTED  AT  REGULAR  INTERVALS. 

without  blurring  the  vision  or  causing  the  eyeballs  to  ache,  they 
should  be  examined  by  a  specialist,  and  if  possible,  properly  fitted 
with  glasses.  It  has  been  found  that  from  thirty  to  sixty  out 
of  every  one  hundred  children  in  the  public  schools  should 
wear  glasses. 


GATEWAYS   OF  THE  MIND  —  SIGHT  221 

The  corners  of  the  eyes  should  be  kept  clean,  and  the  lids 
washed  carefully.  A  disease  which  causes  very  great  soreness 
and  inflammation  of  the  lids  is  due  to  germs  which  breed  inside 
the  lining  of  the  eyelids.  It  is  not  safe  to  use  public  washbasins 
or  towels,  because  of  the  danger  of  getting  the  eyes  infected  with 
these  germs.  Children  suffering  from  this  disease  are  not  allowed 
to  attend  the  public  schools,  because  of  the  danger  of  infecting 
other  children. 

At  home  as  well  as  at  school  and  wherever  the  person  is  who 
has  a  communicable  eye  disease,  the  greatest  care  should  be 
taken  that  the  germs  of  disease  are  not  scattered. 

If  sore  eyes  are  carelessly  rubbed,  germs  are  certain  to  get 
on  the  hands.  If  before  washing  the  hands,  the  patient  uses 
books,  toys,  or  other  things,  some  of  the  germs  are  likely  to  be 
left  on  these  articles.  Other  persons  using  these  things  get  germs 
on  their  hands.  If  one  of  these  persons  rubs  his  eyes  with  un- 
washed hands,  the  circuit  from  diseased  eyes  to  well  ones  will  be 
completed  and  the  seed  will  be  planted  for  another  case  of  eye 
trouble.  One  can  hardly  expect  to  prevent  germs  from  getting  on 
the  hands,  since  whatever  objects  large  numbers  of  people  handle, 
such  as  door  knobs,  stair  railings,  car  straps,  and  school  books, 
are  likely  to  carry  them.  But  one  can  prevent  their  being 
introduced  into  the  eyes,  if  he  heeds  this  most  important  rule : 
Never  rub  the  eyes  with  unwashed  hands. 

As  mentioned  before,  Nature  has  made  careful  provision  to 
protect  the  eyes  from  dust,  for  dust  is  very  injurious  to  them. 
It  irritates  the  lining  of  the  eyelids,  scratches  the  surface  of  the 
eye,  and  may  carry  the  germs  that  cause  inflammation.  If  a 
speck  of  dust,  a  cinder,  or  some  substance  gets  into  the  eye,  do 
not  rub  it,  as  this  may  cause  the  particle  to  become  embedded 
in  the  lining  or  in  the  surface  of  the  eye.  Carefully  draw  the 
upper  lid  over  the  lower.  In  many  cases  this  will  remove  the 


222  KEEPING  THE  BODY   IN  HEALTH 

particle.  Or  holding  up  the  eyelid  and  moving  the  eye  about 
may  remove  it.  It  may  sometimes  be  washed  out  by  bathing 
the  eye. 

Eminent  English  eye  specialists  have  recently  called  atten- 
tion to  the  fact  that  auto-intoxication,  or  general  poisoning  of 
the  body,  which  results  from  lack  of  elimination  of  waste  matters, 
often  causes  serious  injury  to  the  delicate  structures  of  the  eye. 
The  eyes  naturally  deteriorate  with  advancing  age,  but  not  in- 
frequently a  person  of  twenty  who  is  careless  in  regard  to  elimi- 
nation, will  be  found  to  have  an  impairment  of  the  eyes  equal  to 
that  usually  found  in  a  person  fifty  or  sixty  years  of  age.  This 
sort  of  eye  impairment  is  due  to  poisoning  from  wastes  retained 
in  the  body  and  quickly  disappears  when  the  cause  is  removed. 

HEALTH  PROBLEMS 

1.  Can  you  give  any  estimate  of  the  number  of  pictures  that  are  recorded 
in  your  brain  ? 

2.  Why  do  you  think  the  nose  has  been  made  so  prominent,  while  the 
eyes  have  been  set  back  in  sockets? 

3.  Mention  the  different  movements  that  can  be  made  by  the  eye.     Is 
each  movement  of  service  to  us  ?     How  ? 

4.  Make  a  drawing  which  will  show  what  a  concave  shape  is.      Make 
one  that  will  show  a  convex  shape.     What  is  a  good  device  to  use  in  dis- 
tinguishing between  a  convex  and  a  concave  shape  ? 

5.  Can  you  suggest  a  good  test  other  than  the  one  mentioned  in  the 
text  to  show  that  an  image  lasts  after  the  object  from  which  it  is  gained  is 
removed  ? 

6.  Hold  the  pages  of  this  book  before  a  mirror.     What  do  you  notice 
regarding  inversion  and   reversal   of   images?     Is  the  same  thing  true  of 
our  features  when  we  look  at  them  in  a  mirror  ? 

7.  How  near  to  the  eye  can  you  put  a  small  object  and  see  it?    Why 
can  you  not  see  it  when  it  is  brought  nearer  ?    Most  people  after  the  age  of 
fifty  wear  what  is  known  as  bifocal  lenses ;  that  is,  one  part  of  the  lens  is  a 
little  differently  shaped  from  the  other  part.     One  part  is  used  for  reading 


GATEWAYS  OF  THE  MIND  —  SIGHT  223 

and  close  work,  the  other  part  for  looking  at  objects,  farther  away.    Why 
do  not  young  people  have  to  wear  glasses  like  this  ? 

8.  Show  by  a  drawing  why  concave  lenses  are   worn   by  nearsighted 
people, -and  convex  lenses  by  farsighted  people. 

9.  Suggest  an  experiment  which  will  illustrate  some  of  the  ways  in  which 
people  fatigue  their  eyes. 


REVIEW  QUESTIONS 

1 .  WThy  is  it  proper  to  speak  of  the  senses  as  the  gateways  of  the  mind  ? 

2.  Which  is  the  most  remarkable  of  the  gateways  of  the  mind  ? 

3.  How  do  impressions  get  from  the  back  of  the  eyeball  to  the  brain? 

4.  How  do  we  know  that  a  record  is  made  in  the  brain  when  we  look 
at  an  object  ? 

5.  How  are  pictures  made  on  the  retina? 

6.  How  do  the  eyelids,  eyelashes,  and  eyebrows  help  to  protect  the 
eye  from  injury  ? 

7.  What  is  Nature's  provision  for  preventing  the  overflow  of  moisture 
of  the  eye?     How  are  the  tears  drained  away? 

8.  What  is  the  name  of  the  gland  in  which  the  tears  are  formed  ?     Where 
is  it  situated  ? 

9.  How  many  muscles  arc  provided  for  each  eye?     How  are  these  at- 
tached to  the  eye  ? 

10.  What  is  the  outer  coat  of  the  eye  called?    The  middle  coat?    The 
inner  coat  ? 

11.  How  is  the  sclerotic  coat  formed? 

12.  What  is  the  cornea ?     Where  is  it  located,  and  what  is  its  work? 

13.  Where  is  the  choroid  situated?     What  work  does  it  have  to  do? 
Where  is  the  iris,  and  what  is  its  work? 

14.  Where  is  the  pupil  of  the  eye? 

15.  Where  is  the  crystalline  lens,  and  what  is  its  office  in  the  eye? 

1 6.  What  is  a  convex  lens? 

17.  Describe  the  toy  which  is  designed  to  show  that  an  image  of  an 
object  lasts  a  little  time  after  the  object  disappears. 

18.  Why  is  it  that  an  image  on  the  retina  is  inverted  and  the  sides  re- 
versed ? 

19.  What  happens  to  the  image  when  the  distance  of  the  object  at  which 
one  is  looking  is  changed  ? 


224  KEEPING  THE  BODY  IN  HEALTH 

20.  What  happens  to  the  lens  when  the  amount  of  light  entering  the 
eye  is  increased  or  decreased  ? 

21.  How  is  it  possible  for  the  lens  to  become  thicker  or  thinner? 

22.  What  sort  of  work  may  fatigue  the  muscles  controlling  the  lens? 

23.  What  causes  nearsightedness ?    What  causes  farsightedness? 

24.  What  kind  of  glasses  must  a  nearsighted  person  wear?     What  sort 
should  be  worn  by  a  farsighted  person  ? 

25.  Describe  the  care  that  should  be  taken  of  the  eyes  in  reading. 

26.  From  what  side  should  the  light  fall  upon  any  work  we  are  doing? 

27.  What  troubles  are  likely  to  come  from  defective  eyesight? 

28.  What  care  should  be  taken  to  protect  the  eyes  from  dust  and  the 
like? 


CHAPTER  XVI 

GATEWAYS  OF  THE  MIND  —  HEARING 

EACH  special  sense  organ  gives  us  peculiar  sensations  which 
cannot  be  given  by  any  other  organ.  The  eye  gives  sensations 
of  light,  and  the  ear  sensations  of  sound.  A  little  experiment 
will  help  to  make  clear  to  us  what  it  is  that  causes  the  sensa- 
tion of  sound.  Rest  one  end  of  a  board  upon  a  table,  holding 
it  in  position  with  the  left  hand.  Then  draw  a  pin  across  the 
board  with  the  right  hand,  and  you  will  notice  that  the  board 
trembles  or  vibrates.  If  you  now  press  your  head  against  the 
upper  end  of  the  board  and  draw  the  pin  across  it  again,  a  loud 
sound  will  be  heard.  The  vibrations  of  the  board  will  be  com- 
municated through  the  ear  to  the  nerves  of  hearing.  We  can 
hear  the  scratching  of  the  pin,  even  though  we  do  not  place  the 
ear  against  the  board,  because  the  vibrations  of  the  board  start 
vibrations  in  the  surrounding  air  and  these  sound  waves  are 
brought  to  the  ear.  When  the  string  of  a  violin  or  harp  is  made 
to  " sound,"  you  can  see  that  it  is  in  rapid  vibration,  and  the 
same  thing  takes  place  in  all  sounding  bodies. 

You  can  get  some  idea  of  how  sound  travels  by  another  simple 
experiment.  Throw  a  stone  into  the  calm  water  of  a  pond. 
You  will  see  that  a  little  ring  of  waves  forms  itself  at  the  point 
where  the  stone  struck  the  water,  and  that  these  waves  travel  in 
all  directions,  as  far  as  the  water  extends.  If  a  piece  of  wood  is 
made  to  float  upon  the  water,  it  will  bob  up  and  down  as  the 
wave  reaches  it,  being  set  in  motion  by  the  movement  that  was 

225 


226 


KEEPING  THE   BODY  IN  HEALTH 


started  in  the  water  by  the  stone.  Sound  waves  are  made  in 
the  air  by  the  vibration  of  sounding  bodies  in  somewhat  the  same 
way  that  the  waves  are  made  in  the  water  by  the  falling  stone. 
These  sound  waves  traveling  through  the  air  reach  the  inner  ear 
and  set  its  movable  parts  in  motion,  as  the  wave  in  the  water 
sets  the  piece  of  wood  in  motion. 

We  see,  then,  that  sound  is  the  impression  produced  on  us 
when  the  vibrations  of  the  air  strike  on  the  drum  of  the  ear. 
How  we  When  the  vibrations  are  few,  the  sound  is  deep  and 
hear  }ow .  anci  when  they  increase  in  number,  it  becomes 

shriller  and  higher.  The  lowest  sound  that  can  be  heard  by  the 
human  ear  is  made  by  about  sixteen  vibrations  in  a  second. 
When  the  number  reaches  40,000  in  a  second,  the  sound  can- 
not be  heard  by  the  human  ear. 

Think  what  a  great  variety  of  air  movements  there  must  be 
in  order  to  cause  all  the  kinds  of  noises  we  hear.  Yet  all  these 
can  be  received  by  the  ear  and  sent  to  the  brain ;  and  each 

keeps  its  own  peculiar 
quality.  So  sensitive  is 
the  ear  that  we  can  at 
once  recognize  a  familiar 
voice,  even  though  we  do 
not  see  the  face  of  the 
speaker.  Let  us  take  a 
look  inside  the  ear  and 
examine  the  wonderful 

Membrane  Timpani' 

BY  MEANS  OF  THIS  WONDERFUL  MECHANISM  WE    mechanism   by  which  the 

ARE    ABLE    TO    HEAR.       SEE    IF    YOU    CAN    TELL      WOrk    Of    hearillg  is   done. 

WHAT  EACH   PART   OF   THE   MECHANISM  DOES    TO 

ENABLE    US  TO  HEAR.  (l)     What     IS      Called      tllC 

outer  ear  is    (a)   the  part 

that  we  can  see,  and  that  we  commonly  speak  of  as  "the  ear," 
and  (b)  the  auditory  canal  or  tube  through  which  the  vibrations 


terno/  Carioloffar 


Pinna 


GATEWAYS  OF  THE   MIND  — HEARING  227 

pass  to  the  drum.     The  ear  that  we  see  is  placed  where  it  is  for 
the  purpose  of  gathering  up  sound  waves.     You  will  often  see  a 
person  who  is  a  little  deaf  placing  the  hand  behind  the  The  parts 
ear  to  assist   it  in  gathering  up  sound  waves.     Ear  of  the  ear 
trumpets  are  also  used  for  this  purpose.     The  drum  is  a  mem- 
brane (the  tympanic  membrane)  stretched  across  the  lower  end  of 
the  canal.     It  vibrates  like  the  head  of  a  drum  when  the  sound 
waves  strike  upon  it.     Glands  along  the  canal  secrete  the  wax 
which  guards  the  entrance  to  the  drum. 

(2)  The  middle  ear,  or  drum  cavity,  is  connected  with  the 
throat  or  pharynx  by  a  small  canal  called  the  eustachian  tube. 
The  object  of  this  tube  is  to  allow  a  change  of  air  in  the  drum 
cavity  so  as  to  keep  it  at  about  the  same  density  or  pressure  as 
the  air  outside.  Otherwise  the  tympanic  membrane  might  be 
bulged  inward  or  outward  by  the  unequal  pressure  on  its  two 
sides. 

The  air  in  the  ear  may  be  changed  in  the  following  manner : 
Take  a  full  breath  and  then  hold  the  nose  tightly  closed  by 
grasping  it  between  the  thumb  and  finger.  Keep  the  mouth  shut 
and  try  to  force  the  air  out.  As  the  air  cannot  pass  out  through 
the  nose  or  mouth,  it  is  forced  up  through  the  eustachian  tube 
to  the  middle  ear.  It  cannot  pass  through  the  ear,  unless  the 
drum  membrane  has  been  torn.  When  an  opening  has  been 
made  in  the  membrane,  a  whistling  sound  may  be  heard  when 
the  ears  are  inflated  in  this  way.  This  inflation  of  the  ears 
should  not  be  repeated  very  frequently,  but  it  may  some- 
times give  relief  and  restore  the  hearing  when  the  ears  are 
"stuffed  up"  by  a  cold. 

Passing  across  the  middle  ear,  from  its  outer  to  its  inner  side, 
is  a  chain  of  three  very  small  bones  (the  hammer,  anvil,  and 
stirrup).  These  bones  are  bound  together  and  attached  to  the 
walls  of  the  drum  cavity  by  ligaments.  They  are  arranged  in 


228  KEEPING  THE  BODY  IN  HEALTH 

such  a  way  that  when  the  drum  membrane  is  made  to  vibrate 
by  sound  waves,  the  motion  is  communicated  by  them  to  the 
cochlea.  The  cochlea  is  given  this  name  because  it  is  shaped 
like  a  snail  shell.  It  contains  a  great  number  of  nerve  fibers 
of  different  lengths  and  is  thought  to  be  the  part  of  the  ear  which 
distinguishes  musical  notes. 

(3)  The  cochlea  is  situated  at  the  entrance  to  the  inner  ear, 
which  consists  of  small  bony  spaces  and  tubes  called  the  bony 
labyrinth,  within  which  is  a  membranous  labyrinth.  The  mem- 
branous labyrinth  is  lined  with  very  sensitive  cells,  between 
which  are  the  endings  of  the  nerve  fibers  that  connect  the  ear 
with  the  brain. 

We  can  now  get  some  idea  of  what  takes  place  every  time  we 
hear  a  sound.  The  vibrations  or  sound  waves  are  concentrated 
by  the  outer  ear.  They  strike  upon  the  drum,  and  are  com- 
municated from  it  to  the  chain  of  small  bones  which  transmit 
it  to  the  inner  ear,  where  it  makes  an  impression  upon  the  sensi- 
tive nerve  endings.  This  impression  is  transmitted  through  the 
auditory  nerve  to  the  brain,  producing  the  sensation  of  sound. 

The  ears  have  no  lids  or  natural  covering  by  means  of  which 
they  can  shut  out  sound  as  the  eyelids  shut  out  light.  The 
nerves  of  the  ear  remain  active  during  sleep,  reporting  all  noises 
to  the  brain.  The  sounds  to  which  one  is  accustomed  do  not 
prevent  sleep,  although  impressions  brought  to  the  brain  through 
the  ear  are  often  curiously  woven  into  dreams.  Unusual  sounds 
generally  cause  awakening.  Why? 

An  examination  of  hundreds  of  children  in  Europe  showed 
that  one  quarter  of  them  were  a  little  deaf,  many  of  them  with- 
The  care  out  knowing  anything  about  it.  Children  are  some- 
of  the  ears  times  thought  to  be  dull  and  inattentive  when  the 
real  trouble  is  that  they  do  not  hear  well  what  is  said  to  them. 

It  is  a  good  thing  to  have  the  ears  tested  to  find  out  if  the 


GATEWAYS  OF  THE  MIND  — HEARING 


229 


hearing  is  perfect.  A  simple  test  which  you  can  make  for  your- 
self is  to  find  out  how  far  away  you  can  hear  the  ticking  of  a 
watch.  If  your  hearing  is  good,  you  should  be  able  to  hear  the 
watch  when  it  is  held  as  much  as  six  feet  away  from  your  ear. 


ONE  SHOULD  BE  ABLE  WITH  EACH  EAR  TO  HEAR  A  WATCH  TICK  AT  A  DISTANCE  OF  SIX  FEET. 
THE  EYES   SHOULD  BE  CLOSED  WHEN  THE  TEST  IS  MADE. 


If  you  hear  very  much  better  with  one  ear  than  with  the  other, 
or  if  you  cannot  hear  the  watch  tick  at  a  distance  of  more 
than  forty  inches,  your  ears  should  be  examined. 

Sometimes  a  cold  will  cause  deafness  for  a  time.     Catarrh  of 


230  KEEPING  THE  BODY  IN  HEALTH 

the  nasal  passages  or  of  the  throat  may  spread  to  the  eustachian 
tube  and  cause  serious  trouble.  One  who  wishes  to  have  good 
hearing  will  be  careful  not  to  take  cold.  Diseased  tonsils  are 
often  a  cause  of  deafness  and  on  this  account,  as  well  as  for 
other  reasons,  should  be  removed.  Both  ears  should  be  carefully 
examined  whenever  the  tonsils  are  known  to  be  diseased. 

Children  sometimes  shout  or  blow  into  each  other's  ears  for 
fun.  This  is  very  dangerous.  It  may  send  such  a  strong  air 
current  down  the  canal  as  to  rupture  the  drum  membrane  and 
cause  total  deafness.  A  blow  on  the  ear  or  on  the  side  of  the 
head  may  also  seriously  injure  the  ear. 

The  drum  may  be  torn  and  the  hearing  injured  by  using  a 
sharp  instrument,  such  as  a  pin  or  a  toothpick,  to  clean  out  the 
ear.  The  wax  in  the  ear  is  placed  there  by  nature  as  a  protection 
and  ordinarily  should  be  left  undisturbed.  If  the  ears  are  care- 
fully washed  and  wiped  out  every  day,  there  will  be  little  danger 
that  the  wax  will  harden  and  cause  trouble. 

If  anything  accidentally  gets  into  the  ear,  do  not  work  at  it. 
Hold  the  head  over  to  one  side  while  water  is  sprayed  into  the 
ear  from  a  syringe.  If  an  insect  gets  into  the  ear,  a  little  oil 
will  kill  it  so  that  it  can  be  removed  or  will  make  it  come  out. 


HEALTH  PROBLEMS 

1.  See  if  you  can  prove  that  the  head  of  a  drum  vibrates  when  it  is 
struck.     See  also  if  you  can  prove  that  a  tuning  fork  vibrates  when  it  is 
giving  forth  sound. 

2.  Show  whether  the  receiver  of  the  telephone  is  like  the  drum  of  the 
ear  in  any  respect. 

3.  Is  "eardrum"  a  fitting  term  to  apply  to  the  membrane  in  the  ear 
upon  which  sound  waves  strike  ?    Why  ? 

4.  Try  to  imagine  what  goes  on  in  the  ear  when  one  is  walking  along 
a  very  noisy  city  street.    Do  you  think  this  is  good  for  the  ear?    Why? 


GATEWAYS  OF  THE  MIND  — HEARING  231 

5.  Suppose  the  outer  ear  should  be  lost,  what  would  be  the  effect  upon 
the  hearing  ? 

6.  If  you  go  from  a  low  plain  to  the  top  of  a  high  mountain,  which 
way  will  the  eardrum  bulge  when  you  reach  the  top  ?    Why  ? 

7.  When  a  person,  in  crossing  a  mountain,  has  trouble  with  his  ears, 
physicians  try  to  open  up  the  eustachian  tubes.    Why? 

8.  Why  can  one  usually  sleep  soundly  when  the  wind  is  blowing  moder- 
ately or  when  his  bedroom  is  near  the  edge  of  a  lake  or  river  where  the 
water  can  be  heard  lapping  on  the  shore  ? 

REVIEW  QUESTIONS 

1.  Describe  the  experiment  which  was  made  to  show  what  it  is  that 
gives  the  sensation  of  sound. 

2.  What  are  sound  waves? 

3.  How  can  one  illustrate  the  traveling  of  sound  waves  by  throwing  a 
stone  into  the  calm  water  of  a  pond  ? 

4.  What  is  the  eardrum  ? 

5.  Why  is  it  that  some  sounds  are  higher  than  others? 

6.  What  is  the  smallest  number  of  vibrations  a  second  that  the  ear 
can  hear  ?    What  is  the  largest  number  ? 

7.  What  makes  it  possible  for  us  to  recognize  the  voice  of  a  friend? 

8.  What  is  the  outer  ear? 

9.  Where  is  the  auditory  canal? 

10.  Where  is  the  eustachian  tube?    How  does  it  assist  in  hearing? 

11.  What  is  likely  to  happen  when  the  eustachian  tube  becomes  clogged? 

12.  Describe  the  three  small  bones  in  the  middle  ear. 

13.  Just  what  takes  place  in  the  ear  when  we  hear  a  sound? 

14.  Is  there  anything  in  the  ear  corresponding  to  the  eyelid  which 
covers  the  eye  ? 

15.  Can  one  shut  out  noises  during  sleep? 

16.  What  kind  of  noises  are  likely  to  keep  one  awake? 

17.  How  can  one  test  his  hearing  to  find  out  whether  it  is  normal? 

18.  Why  will  a  cold  sometimes  cause  deafness?    It  is  said  that  catarrh 
often  causes  deafness.    How  is  this  possible  ? 

19.  Should  children  shout  into  the  ears  of  one  another?    Why? 

20.  What  may  be  the  effect  upon  the  eardrum  of  a  blow  on  the  ear? 
What  is  the  danger  of  using  a  toothpick  or  a  pin  in  the  ear  ? 


CHAPTER  XVII 


GATEWAYS  OF  THE  MIND  —  SMELL,  TOUCH,  AND  TASTE 

PERHAPS  you  know  that  the  sense  of  smell  does  not  play  so 
important  a  part  in  the  life  of  human  beings  as  it  does  in  the  life 
of  some  of  the  lower  animals.  Do  you  think  it  may  be  that  it 

has  been  largely  lost  in 
through  neglect  of 
In  a  dog  this  sense 
acute  that  it  seems 

^/factory 


JVerves 


man 

use? 

is  so 

often  to  be  of  more  service 

than  the  sense  of  sight. 

The  olfactory  nerves,  or 
nerves  of  smell,  end  in  the 
mucous  membrane  of  the 
upper  part  of  the  nasal 

THIS  DIAGRAM  OF  THE  NASAL  CAVITY  SHOWS  THE  r*-\nt\r  WAT-^   a  TV* 

OLFACTORY    NERVES.       THESE     ARE     THE     ONLY  ™\\? . 

NERVES  IN  THE  BODY  EXPOSED  TO  THE  OUTSIDE  delicate  Cells  VCty 

WORLD.                                                                                                                   j  m, 

to  odors.  These  are  the 

only  nerve  cells  in  the  body  exposed  to  the  outside  world.  From 
the  olfactory  cells  in  the  nose,  nerve  fibers  pass  to  the  brain. 

The  sense  of  smell  is  excited  only  by  very  small  particles  of 
certain  substances  brought  to  these  sensitive  cells  by  moving  air. 
This  is  why  we  "  sniff "  the  air  when  we  wish  to  smell  anything. 

When  substances  having  an  odor  are  held  in  the  mouth,  the 
particles  that  give  the  sensation  of  odor  are  carried  through  the 
nose  by  the  outgoing  breath.  Those  sensations  of  smell  we 
often  confuse  with  taste.  We  frequently  think  we  taste  some- 

232 


SMELL,  TOUCH,  AND  TASTE  233 

thing  which  in  reality  we   only  smell.      Try  this  experiment, 
hold  the  nose  so  that  the   breath  cannot  escape  through  it, 
while  a  piece  of  onion  is  held  on  the  tongue.     You  confusing 
will  then  notice  that  you  cannot  taste  the  flavor  of  smell  and 
the  onion.     When  the  nose  is  obstructed  by  a  cold  taste 
the  sense  of  smell  is  greatly  lessened  or  even  lost  for  a  time.    At 
such  times  the  most  highly  flavored  substances  seem  to  have 
little  or  no  taste. 

Neglected  colds,  which  result  in  chronic  catarrh  of  the  nasal 
passages,  may  lead  to  entire  loss  of  the  sense  of  smell.     The 
mucous  membrane  may  become  thickened,  so  that  the  Destroying 
odorous  particles  carried  by  the  air  cannot  come  in  the  sense 
contact  with  the  nerves  of  smell.     The  use  of  snuff  and  of  sme11 
cigarettes  are  also  likely  to  be  destructive  to  this  useful  sense. 
Tobacco  smoke  has  a  paralyzing  effect  upon  the  nerves,  besides 
inflaming  the  mucous  membrane. 

The  brain  receives  valuable  information  through  the  sense  of 
smell,  as  well  as  the  pleasurable  sensations  caused  by  delightful 
odors.  It  helps  us  in  determining  whether  articles  are  fit  for 
food.  Food  that  is  beginning  to  spoil  usually  gives  forth  an 
unpleasant  odor.  The  sense  of  smell  also  warns  us  of  the  pres- 
ence of  poisonous  gases  in  the  air.  It  is  a  signal  placed  at  the 
entrance  of  the  body,  and  its  warnings  should  be  promptly 
heeded.  When  neglected,  it  soon  ceases  to  give  warning  of  the 
presence  of  danger.  This  is  shown  by  the  sensation  experienced 
on  entering  an  unventilated  bedroom,  or  a  crowded  room,  after 
a  walk  out  of  doors.  The  new  arrival  is  surprised  that  the 
persons  in  the  room  can  endure  the  unpleasant  odor  which  he 
at  once  recognizes.  But  if  he  remains  in  the  room  for  some  time, 
he  soon  becomes  as  unconscious  of  it  as  the  others. 

Examine  your  tongue,  and  you  will  find  on  its  surface  many 
little  prominences  which  are  called  papilla.  If  you  look  closely 


234  KEEPING  THE  BODY  IN  HEALTH 

enough,  you  will  notice  some  large  papillae  that  project  quite 
prominently  above  the  others.  These  large  ones  are  called 
The  sense  ^e  P*1^®  circumvaUatet  because  there  is  a  little 
of  taste,  a  valley  or  furrow  surrounding  each  one.  The  purpose 
sentinel  of  of  this  little  trough  is  to  receive  the  fluids  of  the 
the  body  mOuth  in  which  are  dissolved  the  savory  substances 
of  the  food.  In  the  trough  ara  the  taste  buds,  each  one  of  which 
is  the  expanded  end  of  a  bunch  of  nerves.  These  taste  buds  are 
made  up  of  thousands  of  delicate  nerve  filaments  which  by 
means  of  their  arrangement  are  brought  into  direct  contact 
with  the  liquids  containing  the  flavors  of  the  food.  If  these 
sensitive,  jellylike  masses  were  right  on  the  surface  of  the  tongue, 
they  would  soon  be  injured.  They  are  protected  by  being 
hidden  away  down  in  these  little  grooves.  (See  page  27.) 

The  flavor  of  many  substances  that  we  think  we  taste  is  really 
due  to  the  odor,  as  we  noticed  above.  There  are  only  four  true 
taste  sensations:  sweet,  sour,  salt,  and  bitter.  It  has  been 
shown  that  each  of  these  is  recognized  by  a  special  set  of  nerves. 
Bitterness  is  most  distinctly  recognized  at  the  back  of  the 
tongue,  and  the  other  flavors  at  the  tip  and  sides. 

Should  you  expect  that  condiments,  such  as  mustard  and 
pepper,  and  all  substances  which  burn  the  tongue,  would  injure 
the  nerves  of  taste  and  lessen  their  ability  to  recognize  flavors? 
Why  ?  Should  you  expect  that  alcohol  would  paralyze  the  nerves 
of  taste?  Why?  A  teaspoonful  of  alcohol  held  in  the  mouth 
for  a  few  minutes  will  so  benumb  the  nerves  that  ordinary 
flavors  cannot  be  detected.  The  habitual  use  of  alcohol  per- 
manently injures  this  valuable  sense. 

The  sense  of  taste  is  given  to  us  not  merely  as  a  means  of  pleas- 
ure but  as  a  guide  to  our  appetites.  It  is  one  of  the  most 
important  safeguards  of  the  body.  The  old  proverb,  "  Hunger 
is  the  best  sauce,"  is  a  true  one,  because  when  we  are 


SMELL,  TOUCH,  AND  TASTE 


235 


hungry  almost  any  sort  of  wholesome  food  can  be  eaten  with 
relish.  When  the  sense  of  hunger  is  satisfied  the  food  no  longer 
tastes  so  good.  A  natural  taste  is  a  sentinel  which  promptly 
indicates  to  the  eater,  whenever  this  is  necessary,  that  enough 
of  any  sort  of  food  has  been  taken  to  satisfy  his  present  needs. 

Another  important  avenue  to  the  mind,  through  which  a  great 
amount  of  valuable  information  comes  to  us,  is  the  sense  of  touch. 
The  nerve  endings  of  this  sense  are  in  the  skin.     Wher-  The  sense 
ever  these  nerves  are  most  abundant,  the  sense  of  of  touch 
touch  is  most  acute,  —  in  the  ends  of  the  fingers,  the  lips,  and 
the  tip  of  the  tongue.     When 
we  touch  anything,  the  outer 
skin  or  epidermis  is  pressed 
upon  these  nerve  endings,  and 
an  impulse  is  started  to  the 
brain,  causing,  a  sensation  of 
feeling. 

The  mind  is  able  to  discern 
many  of  the  characteristics 
of  objects  through  the  sense 
of  touch.  By  its  aid  we  are 
able  to  distinguish  the  forms  of 
objects,  and  can  tell  whether 
they  are  smooth  or  rough, 
hard  or  soft,  rigid  or  elastic. 
A  little  baby,  reaching  out 
with  its  hands  to  take  hold  of 
everything  it  sees,  is  mak- 
ing an  unconscious  effort 
to  inform  its  mind  and 
develop  its  judgment  by  means  of  the  sensation  of  feeling. 

The  delicacy  of  the  sense  of  touch  may  be  greatly  increased 


IN  THE  BLIND  THE  SENSE  OF  TOUCH  BECOMES 
VERY  ACUTE,  BECAUSE  IT  MUST  TAKE  THE 
PLACE  OF  SIGHT. 


236  KEEPING  THE  BODY  IN  HEALTH 

by  cultivating  it.  In  the  blind,  in  whom  it  has  to  take  the  place 
of  the  sense  of  sight,  it  is  very  acute. 

The  attainments  possible  through  long  training  of  the  sense 
of  touch  is  shown  in  the  case  of  Helen  Keller,  who  lost  both 
sight  and  hearing  before  she  was  two  years  old.  From  that  time 
the  only  avenue  to  her  mind  (with  the  exception  of  taste  and 
smell)  was  the  sense  of  touch.  Yet  she  acquired  successfully  a 
college  education  and  has  become  better  informed  than  most 
persons  having  the  use  of  all  their  senses.  It  has  often  been  said 
of  her  that  she  "sees  more  with  her  fingers  than  other  persons 
with  their  eyes." 

Besides  those  that  are  stimulated  by  touch,  there  are  nerves  in 
the  skin  that  are  stimulated  by  heat  and  others  that  are  stimu- 
The  sense  lated.  by  cold.  It  is  a  curious  fact  that  warmth  and 
of  tem-  cold  are  not  felt  on  the  same  spot  of  skin.  The  hot 
perature  spots  and  cold  spots  are  arranged  in  curved  lines  or 
chains,  starting  from  the  hair  roots. 

The  effect  that  may  be  produced  upon  the  body  by  tempera- 
ture, acting  through  the  nerves  that  carry  to  the  brain  the 
sensations  of  heat  and  cold,  has  already  been  studied.  We 
have  seen  that  by  the  stimulation  of  these  nerves,  impulses  may 
be  carried  to  every  organ  and  tissue,  increasing  the  blood  circu- 
lation and  exciting  bodily  activity. 

A  daily  cold  bath  furnishes  good  training  of  the  nerves  and  the 
brain,  as  well  as  of  the  skin  and  its  vessels.  The  impression 
made  by  the  contact  of  the  cold  water  with  the  skin  sends  a 
thrill  from  the  surface  to  the  center,  stirring  every  cell  and 
fiber.  By  the  cold  bath  the  whole  body  is  aroused  and  energized. 

Another  sensation  with  which  we  are  all  familiar  is  pain.  It 
The  use  is  not  known  whether  this  sensation  has  its  own  special 
of  pain  sets  of  nerves,  but  it  is  thought  that  it  is  caused  by 
too  great  stimulation  of  any  of  the  nerves  of  feeling.  Although 


SMELL,  TOUCH,  AND  TASTE  237 

unpleasant  and  hard  to  bear,  pain  is  one  of  the  most  useful 
sensations  that  we  experience.  It  is  a  danger  signal,  calling 
our  attention  to  the  fact  that  something  is  wrong  and  needs 
attention. 

Pain  is  often  a  means  of  preserving  the  body  from  serious 
injury.  For  example,  if  it  were  not  for  the  pain  a  little  child 
might  keep  its  hand  in  a  fire  until  it  was  destroyed.  Toothache 
is  a  warning  that  a  tooth  is  beginning  to  decay,  a  fact  that  other- 
wise might  not  be  discovered  in  time  to  save  the  tooth. 

People  often  try  to  stop  or  kill  pain  by  drugs  or  other  means, 
but  pay  no  attention  to  the  trouble  of  which  the  pain  is  giving 
them  notice.  This  is  as  foolish  as  it  would  be  to  kill  a  sentinel 
because  he  gave  us  warning  of  an  approaching  danger,  and 
then  to  go  on,  making  no  effort  to  avert  the  danger. 

The  wise  thing  to  do  is  not  to  take  some  kind  of  "pain  killer" 
but  to  find  out  what  is  causing  the  pain  and  to  try  as  far  as 
possible  to  have  it  remedied.  This  can  best  be  done  by  con- 
sulting a  reliable  physician  and  acting  upon  his  advice. 

HEALTH  PROBLEMS 

1.  How  does  a  dog  or  other  animal  use  the  sense  of  smell?     Suppose 
the  animal  should  lose  this  sense,  could  it  get  along  without  it  ?    Why  ? 

2.  Do  you  think  the  horse  makes  more  use  of  the  sense   of  sight  than 
of  the  sense  of  smell  ?     Give  reasons  for  your  answer. 

3.  We  say  that  animals  "prick  up  their  ears"  when   their  attention  is 
attracted  by  any  noise.     Do  they  do  anything  resembling  this  when  their 
attention  is  attracted  by  odors  ? 

4.  A  lion  when  he  is  stealing  upon  prey,  or  a  hunter  when  he  is  track- 
ing an  animal,  approaches  against  the  wind.     Why  does  he  do  this  ? 

5.  Suggest  two  or  three  good  tests  to  show  how  the  sense  of  smell  helps 
the  sense  of  taste.     Does  food  with  a  disagreeable  smell  ever  have  a  good 
taste?     If  you  think  so,  give  an  example. 

6.  Why  has  Nature  arranged  for  taste  and  smell  to   work  together  so 
closely  ? 


238  KEEPING  THE  BODY  IN  HEALTH 

7.  Why  has  Nature  arranged  for  some  odors  to  affect  us  pleasantly 
and  for  others  to  affect  us  disagreeably? 

8.  Try  a  bitter  tasting  object  on  the  tip  of  your  tongue  to  see  if  you 
can  detect  the  bitterness. 

9.  Put  something  sour  as  far  back  on  the  tongue  as  possible  to  see  if 
you  can  taste  its  sourness.     Explain. 

10.  Why  does  Nature  arrange  for  an  article  of  food  not  to  taste  so  good 
as  at  first,  when  enough  of  it  has  been  eaten? 

11.  Why  has  Nature  made  the  sense  of  touch  so  acute  in  the  tips  of 
the  fingers,  in  the  lips,  and  on  the  tip  of  the  tongue  ? 

12.  In  what  parts  of  the  skin  is  the  sense  of  touch  very  dull? 

13.  Why  does  fresh  cold  air  help  to  give  one  a  good  appetite? 

REVIEW  QUESTIONS 

1.  How  is  it  possible  for  odors  to  make  an  impression  on  the  brain  ? 

2.  What  is  the  meaning  of  olfactory?    What  are  the  olfactory  cells? 
The  olfactory  nerves  ? 

3.  Why  do  people  "sniff  the  air"  when  they  want  to  smell  anything? 

4.  When  one  has  a  cold  or    catarrh,    why    does   food  often  lose  its 
taste? 

5.  What  is  likely  to  be  the  effect  of  cigarette  smoking  and  snuff  tak- 
ing upon  the  sense  of  smell  ? 

6.  Can  the  sense  of  smell  become  accustomed  to  disagreeable  odors 
so  that  one  cannot  detect  them?     Give  illustrations. 

7.  If  you  examine  the  surface  of  the  tongue,  what  do  you  find  there? 

8.  Where  are  the  taste  buds  ?    Of  what  use  are  they  ? 

9.  Suppose  the  taste  buds  were  on  the  surface  of  the  tongue,  what 
might  happen  to  them  ? 

10.  What  are  the  true  taste  sensations? 

11.  On  what  part  of  the  tongue  is  sourness  recognized?    Where  are  the 
other  flavors  recognized  ? 

12.  What  is  the  effect  on  the  sense  of  taste  of  condiments  such  as  mus- 
tard and  pepper  ? 

13.  What  is  the  effect  of  alcohol  on  the  sense  of  taste? 

14.  Why  is  one's  natural  taste  a  sentinel  ? 

15.  Where  are  the  nerve  endings  for  the  sense  of  touch? 

16.  Where  is  the  sense  of  touch  most  delicate  ? 


SMELL,  TOUCH,  AND  TASTE  239 

17.  What  can  the  mind  find  out  about  objects  through  the  sense  of 
touch  ? 

1 8.  What  is  meant  by  the  "sense  of  temperature"? 

19.  What  effect  may  be  produced  on  the  body  by  cold? 

20.  Why  will  a  cold  bath  stimulate  every  part  of  the  body  ? 

21.  What  is  pain? 

22.  Are  pain  sensations  useful  to  the  body?    Explain. 

23.  What  is  it  wise  to  do  when  attacked  by  pain? 


CHAPTER  XVIII 

Two  ENEMIES  OF  THE  BODY  —  ALCOHOL  AND  TOBACCO 

THE  first  thing  that  any  one  who  wants  good  health  should  do 
is  to  guard  against  the  enemies  of  the  body.  We  have  already 
learned  about  some  of  these  enemies ;  but  we  must  give  special 
attention  in  this  chapter  to  two  of  these,  because  of  the  great 
harm  they  will  do  the  body  unless  we  can  avoid  them. 

There  are  certain  poisonous  substances,  very  harmful  to  the 
body,  which  are  yet  capable  of  giving  rise  for  the  moment  to 
pleasurable  sensations.  They  give  one  a  feeling  of  happiness,  of 
well-being,  or  comfort.  For  this  reason,  they  have,  come  to  be 
largely  used  by  human  beings,  in  spite  of  their  poisonous  character. 
Among  those  chiefly  used  in  this  country  are  alcohol  and  tobacco. 

Alcohol  is  closely  allied  to  naphtha,  benzine,  and  kerosene, 
which  no  one  would  think  of  drinking.  In  a  pure  state,  alcohol 
destroys  instantly  all  living  tissues  with  which  it  comes  in  con- 
tact. It  is  seldom  found  pure,  usually  containing  from  two  to 
fifty  per  cent  of  water. 

If  a  plant  be  watered  with  diluted  alcohol,  its  leaves  will  soon 
wither  and  turn  yellow;  and  the  plant  will  die.  A  tadpole 
Alcohol  dropped  into  a  vessel  containing  alcohol  will  die  in  a 
kills  living  minute.  Alcohol,  taken  even  in  small  doses,  has  an 
things  injurious  effect  upon  the  living  tissues  of  the  body. 

A  curious  accident  which  happened  to  a  hunter  many  years  ago 
made  it  possible  to  find  out  the  exact  effect  which  alcohol  has 
upon  the  stomach.  A  Canadian  trapper  and  hunter,  named 
Alexis  St.  Martin,  was  shot  in  the  stomach.  The  wound  was  so 
large  that  the  flesh  did  not  close  up  and  heal  the  wound  in  the 

240 


TWO  ENEMIES  OF  THE   BODY  241 

usual  way.  It  healed  only  the  edges,  leaving  a  hole  two  and  one 
half  inches  around.  A  fold  of  lining  of  the  stomach  hung  down 
and  formed  a  kind  of  curtain  over  the  opening.  This  could  be 
pushed  back  so  that  one  could  look  in  and  see  what  went  on 
in  the  man's  stomach,  just  as  Professor  Pavlov  was  able  to  look 
into  the  stomachs  of  his  dogs. 

Dr.  Beaumont,  a  physician  in  the  United  States  Army,  in- 
vited this  man  with  a  window  in  his  stomach  to  come  and  live 
with  him.  He  wanted  to  be  able  to  look  in  whenever  he  pleased, 
and  see  just  how  the  stomach  acted  under  different  conditions. 
Among  other  things,  he  wanted  to  find  out  if  alcohol  was  help- 
ful to  the  stomach  in  its  work  or  if  it  hindered  it  and  injured  it. 

Dr.  Beaumont  noticed  that  when  Alexis  was  given  good  food 
with  no  alcohol,  the  stomach  lining  was  of  a  pink  color,  and  the 
gastric  juice  was  thin  and  colorless.  Then  he  tried  giving  him  a 
small  amount  of  alcohol  every  day.  He  soon  noticed  that  the 
lining  became  of  a  red  color,  because  it  was  irritated  and  inflamed 
by  alcohol.  After  a  while,  small  sores  or  ulcers  formed  on  it. 
He  removed  some  of  the  gastric  juice  with  a  tube  and  found 
that  it  contained  a  thick  mucus  and  sometimes  blood  from  the 
sore  places.  He  then  stopped  giving  the  alcohol  and  the  stomach 
gradually  healed  and  returned  to  its  natural  pink  color.  By  this 
Dr.  Beaumont  knew  that  the  continued  use  of  alcohol  causes 
disease  of  the  stomach. 

Alcohol  does  more  than  simply  irritate  and  inflame  the  stomach. 
It  is  able  to  paralyze  the  nerves  so   that  they  will  Some  of 
lose  their  sensibility.     On  one  occasion,  when  Alexis  the  effects 
St.  Martin  had  been  drinking  heavily  for  several  days,  °  ^^e 
Dr.  Beaumont  noticed  that  his  stomach  was  much  human 
inflamed   and    ulcerated,    but   Alexis    himself   knew  body 
nothing   about   this.      He   felt  no  pain  or  discomfort   in   his 
stomach  but  only  complained  of  having  a  severe  headache. 


242 


KEEPING  THE  BODY  IN  HEALTH 


The  liver,  as  well  as  the  stomach,  is  injured  by  the  use  of  al- 
cohol. In  one  who  indulges  in  alcohol  for  years,  it  becomes 
shrunken,  hard,  and  almost  useless.  The  outside  becomes 
covered  with  little  knobs  so  that  it  looks  like  the  sole  of  an  Eng- 
lish cartman's  shoe.  The  condition  has  for  this  reason  been 
given  the  name,  " hob-nailed  liver." 

Alcohol  has  the  effect  of  hardening  the  tissues.  The  brain 
in  a  healthy  state  is  so  soft  that  it  would  not  retain  its  exact 
form  if  it  were  not  supported  by  the  skull.  The  sharpest  knife 
is  required  to  cut  it  without  tearing  it.  If  a  careful  examination 

of  a  brain  is  to  be  made, 
it  is  necessary  to  put  it 
in  alcohol  for  weeks  or 
months  in  order  to  harden 
it.  But  the  brain  of  a 
drunkard  is  already  more 
or  less  hardened.  An 
anatomist  declared  that 
he  could  tell  a  drunkard's 
brain  in  the  dark  by  the 
sense  of  touch  alone. 

Experiments  upon  liv- 
ing animals  have  shown 

the  changes  that  take  place  in  the  nerve  cells  when  alcohol  is 
introduced  into  the  circulation.  Some  of  the  cells  almost 
immediately  become  shriveled,  misshapen,  and  incapable  of 
performing  their  duty.  The  delicate  branches  by  which  the 
cells  come  in  contact  with  each  other  are  drawn  back.  The 
contact  of  the  cells  is  thus  interrupted,  and  this  interferes  with 
memory,  reason,  and  judgment.  This  explains,  as  we  have 
seen,  the  mental  disturbances  which  take  place  in  one  who 
drinks  freely  of  alcoholic  beverages. 


Ce.\\  Poisoned  Y>\j 


ALCOHOL  is  A  POISON  WHEN  TAKEN  FREELY.    IT 

AFFECTS  NERVE  CELLS  SO  UNFAVORABLY  THAT 
MEMORY  AND  REASON,  —  IN  FACT,  ALL  THE 
MENTAL  PROCESSES,  —  ARE  IMPAIRED. 


TWO  ENEMIES  OF  THE  BODY  243 

When  an  animal  experimented  upon  with  alcohol  recovers 
from  an  intoxicating  dose,  the  nerve  cells  regain  their  natural 
appearance.  But  when  the  use  of  alcohol  is  habitual  and  long- 
continued,  some  of  the  cells  become  permanently  injured.  Then 
the  brain,  mind,  and  character  are  permanently  Changed. 

Life  insurance  companies  know  that  one  who  uses  alcohol  is 
not  a  "good  risk."  He  is  not  likely  to  live  so  long  as  one  who 
does  not.  Statistics  based  on  their  tables  show  that  the  mor- 
tality of  liquor  users  is  five  hundred  per  cent  greater  than  that 
of  abstainers.  It  has  also  been  shown  that  at  twenty  years  of  age, 
a  temperate  man  has  an  average  chance  of  living  for  forty-four 
and  one  fifth  years,  while  the  drinking  man  has  the  prospect  of 
only  fifteen  and  one  half  years. 

The  effects  of  alcohol  are  often  seen  even  more  plainly  in  the 
children  of  those  who  use  it  than  in  the  users  themselves.  A 
French  physician,  Dr.  Legrain,  made  some  investigations  to  find 
out  what  effect  alcohol  had  upon  the  children  of  parents  who 
used  it  freely.  This  is  what  he  found:  "In  the  first  genera- 
tion from  inebriety  the  mental  and  physical  degenerates  were 
77  per  cent  of  all;  in  the  second  generation,  96  per  cent  were 
defectives ;  in  the  third  generation  not  one  escaped ;  all  were 
idiots,  insane,  hysterical,  or  epileptic." 

All  these  things  show  us  that  alcohol  is  a  deceiver;    it  only 
increases  all  the  miseries  that  it  promises  to  relieve.     It  relieves 
hunger,  because  it  takes  away  the  appetite  and  the  Alcohol  a 
power  to  digest  food ;  but  it  does  not  nourish  the  body,  deceiver 
It  soothes  pain  by  paralyzing  the  nerves,  but  it  does  not  remove 
the  cause  of  the  pain.     If  a  man  is  cold,  it  gives  him  the  sensa- 
tion of  warmth,  but  he  is  actually  colder  than  before.    It  makes 
the  weak  man  feel  strong,  but  he  is  actually  weaker  than  before. 
It  causes  the  nervous  system  to  falsify  and  to  make  a  man  think 
he  is  happy,  while  he  is  all  the  time  becoming  more  wretched, 


244 


KEEPING  THE  BODY  IN  HEALTH 


In  1862  the  attention  of  the  French  Emperor  was  called  to 
the  fact  that  the  number  of  lunatics,  paralytics,  and  epileptics 
Tobacco  a  m  ^ne  hospitals  of  France  was  five  times  as  great  in 
cause  of  proportion  to  the  population  as  it  had  been  thirty  years 
disease  before.  There  was  also,  it  was  noticed,  about  five 
times  as  much  tobacco  being  used  as  thirty  years  before.  It  was 
thought  that  there  might  be  some  connection  between  these 
two  things,  and  the  Emperor  appointed  a 
committee  of  scientific  men  to  make  an  in- 
vestigation. 

In  the  course  of  this  investigation,  the 
students  in  the  government  training  schools 
were  divided  into  two  classes  —  smokers  and 
non-smokers.  The  physical  condition  of  each 
class  was  carefully  noted,  as  well  as  the  amount 
of  work  they  were  able  to  do.  It  was  found 
that  the  non-smokers  were  much  superior, 
physically,  mentally,  and  morally,  to  the 
smokers.  A  law  was  at  once  passed  forbid- 
ding the  students  in  the  government  training 
schools  to  use  tobacco. 

Dr.  J.  W.  Seaver,  Professor  of  Physical 
Education  at  Yale,  has  made  a  careful  study 
of  the  influence  of  tobacco  upon  the  bodies  and  minds  of  the 
students.  He  found  that  during  three  and  one  half  years  of 
undergraduate  life,  the  non-smokers  increased  in  height  24  per 
cent  more  than  the  smokers ;  in  girth  of  chest,  26  per  cent 
more;  and  in  lung  capacity  77  per  cent  more. 

A  professor  in  the  Kansas  State  Agricultural  College  recently 
examined  the  condition  of  2500  school  boys  who  smoked  cig- 
arettes. In  one  group  of  twenty-five  school  boys  whose  average 
age  of  beginning  to  smoke  was  thirteen  years,  he  found  the  fol- 


THE  TOBACCO  PLANT 


TWO  ENEMIES  OF  THE  BODY  245 

lowing  conditions :  sore  throat,  4 ;  weak  eyes,  10 ;  pain  in  chest, 
8  ;  short  wind,  21 ;  stomach  trouble,  21 ;  pain  in  heart,  9. 

In  the  high  schools  in  Wisconsin,  it  was  found  that  nearly  all 
the  boys  who  were  dropped  because  of  poor  work  or  who  were 
expelled  for  one  cause  or  another  were  smokers.  Those  who 
used  tobacco  were  almost  always  behind  those  who  did  not 
use  it. 

That  many  boys  and  young  men  are  being  injured  by  smoking 
was  shown  in  the  military  examinations  during  the  late  war. 
The  examining  physicians  had  to  refuse  a  very  large  num- 
ber of  those  who  wanted  to  enlist  in  the  army  because  they 
were  suffering  from  "tobacco  heart"  caused  by  smoking. 

Two  rabbits  made  to  inhale  tobacco  smoke  as  an  experi- 
ment died  within  a  month. 

Bees,  flies,  and  other  insects  are  quickly  killed  by  directing 
upon  them  a  stream  of  tobacco  smoke. 

Nicotine  is  an  oily  liquid  which  is  the  essential  principle  of 
tobacco.  According  to  Professor  Shoemaker,  eight  drops  of 
nicotine  will  kill  a  horse,  two  drops  a  dog,  and  one  twentieth 
of  a  drop  will  kill  a  frog.  Numerous  experiments  have  proved 
that  nicotine  is  a  poison  to  the  heart  and  blood  vessels. 

These  things  show  us  that  tobacco  is  another  of  the  deceiving 
drugs  that  promises  happiness  and  brings  trouble.  It  makes 
slaves  of  its  young  victims,  while  it  gradually  injures  them. 

Tea  and  coffee  are  not  healthful  beverages  because  they  con- 
tain a  nerve  poison,  caffein.  Kola  drinks  also  contain  caffein. 
Tea  and  coffee  produce  sleeplessness  because  caffein  irritates 
the  nerves  and  destroys  the  sense  of  fatigue.  It  is  very  evident 
that  a  drug  which  will  make  it  impossible  for  a  person  to  sleep 
when  he  really  requires  rest  and  sleep  must  be  a  powerful 
poison  and  very  harmful  to  the  nerves.  Caffein  injures  the 
blood  vessels.  On  this  account  tea,  coffee,  and  kola  beverages 


246  KEEPING  THE  BODY  IN  HEALTH 

tend  to  cause  high  blood  pressure.  In  many  persons  a  single 
cup  of  coffee  will  cause  trembling  of  the  hands.  A  person  who 
wishes  to  live  long  and  have  steady  nerves  will  avoid  tea, 
coffee,  and  all  beverages  containing  caffein. 

HEALTH  PROBLEMS 

1.  Put  a  little  alcohol  diluted  one  half  with  water  on  the  leaf  of  a  plant, 
and  describe  what  happens  to  the  leaf. 

2.  Try  putting  some  alcohol  diluted  one  half  on  the  roots  of  a  growing 
house  plant,  and  describe  what  happens  to  the  plant. 

3.  Why  is  it  impossible  for  a  drunken  man  to  reason  or  to  attend  his 
business? 

4.  Why  is   it   that   men  when   intoxicated   often  use  coarse  speech 
which  they  would  not  use  were  they  sober  ? 

5.  Why  do  drunken  men  often  want  to  engage  in  a  brawl? 

6.  In  some  of  the  universities  there  are  delicate  instruments  which 
are  used  to  see  how  quickly  one  can  act  at  a  given  signal  and  how  quickly 
he  can  choose  between  lines  of  action.    It  has  been  found  that  alcohol 
always  interferes  with  rapid  action  and  accurate  choosing.     Explain. 

7.  Why  will  a  man  on  an  athletic  team  be  instantly  dismissed  if  he  is 
caught  indulging  in  alcoholic  drinks  ? 

8.  Judges  say  that  most  crimes  are  due  to  the  use  of  alcohol.     Should 
you  expect  this?    Explain. 

9.  Sometimes  you  hear  men  say  that  if  they  stop  smoking  for  a  while, 
and  then  start  again  they  are  made  sick  by  a  cigar  or  pipe.    Explain. 

10.  China  is  doing  everything  it  can  to  drive  opium  out  of  the  country, 
because,  the  Chinese  say,  it  has  held  back  their  people  for  centuries.  Do 
you  think  tobacco  may  have,  to  some  extent,  the  same  effect  upon  the 
people  in  our  country  ? 

REVIEW  QUESTIONS 

1.  What  poisonous  substances  may  give  pleasurable  sensations  for 
the  moment? 

2.  What  will  alcohol  in  a  pure  state  do  to  any  living  tissue  with  which 
it  comes  in  contact  ? 


TWO  ENEMIES  OF  THE  BODY  247 

3.  Describe  the  accident  which  happened  to  Alexis  St.  Martin  and  the 
study  that  was  made  of  his  stomach. 

4.  What  was  found  regarding  the  effects  of  alcohol  on  the  stomach  of 
St.  Martin? 

5.  How  does  alcohol  affect  the  nerves  ? 

6.  How  does  alcohol  affect  the  liver? 

7.  What  is  meant  by  "  hob-nailed  liver  "  ? 

8.  If  a  brain  is  placed  in  alcohol,  what  change  will  take  place  in  it? 

9.  Why  can  an  expert  anatomist  tell  a  drunkard's  brain  in  the  dark 
by  the  sense  of  touch  alone  ? 

10.  What  happens  to  the  nerve  cells  when  alcohol  is  put  into  the  blood  ? 

11.  What  do  life  insurance  companies  say  about  the  use  of  alcohol? 
Will  they  insure  a  man  who  does  not -drink  liquor  for  less  than  they  will 
insure  one  who  does  ?     Why  ? 

12.  Is  it  right  to  speak  of  alcohol  as  a  deceiver?    How  does  it  deceive 
one? 

13.  What  did  the  French  government  find  aoout  the  effects  of  tobacco 
upon  the  nerves  of  the  people  of  France  ? 

14.  Why  was  a  law  passed  in  France  forbidding  the  students  of  govern- 
ment training  schools  to  use  tobacco  ? 

15.  What  has  Doctor  Seaver  of  Yale  University  found  regarding  the 
effects  of  tobacco  ? 

1 6.  Why  are  coffee,  tea,  and  kola  drinks  harmful?    What  are  some  of  the 
noticeable  effects  of  these  drinks? 


CHAPTER  XIX 

OTHER  ENEMIES  OF  THE  BODY  —  DISEASE  GERMS 

IN  this  chapter,  we  must  bring  together  an  we  have  learned 
about  those  deadly  enemies  of  the  body,  disease  germs,  and  add 
some  new  facts.  When  there  i?  an  outbreak  of  disease  in  a 
community,  some  of  the  people  exposed  to  the  germs  take  the 
disease,  become  very  sick,  and  perhaps  die,  while  others  escape 
entirely.  Why  do  not  all  the  people  exposed  to  the  germs  be- 
come sick? 

A  healthy  human  body  is  able  to  defend  itself  quite  well  against 
all  kinds  of  germs.  Only  when  they  attack  in  overwhelming 
numbers,  or  when  the  natural  defenses  of  the  body  have  been 
weakened,  are  they  able  to  gain  a  foothold  in  the  body.  Yet  in 
the  warfare  that  is  constantly  going  on  between  mankind  and 
these  invisible  foes,  a  large  part  of  the 
human  race  is  destroyed.  What  are  some 
of  the  reasons  for  this? 

You  know  already  that  when  we  speak 
of  disease  germs  we  refer  to  those  little 
plants   (bacteria)  and   animals    (protozoa} 
that  are  capable  of  growing  in  the  bodies 
YELLOW' FEVER  GE^MS  ARE    of  human  beings  and  animals  and  causing 
CARRIED  BY  A  MOSQUITO.      disease.     Where  are  these  most  likely  to 

be  found? 

You  have  learned  that  the  germs  of  tuberculosis  may  be  blown 
about  in  the  dust  of  the  street  and  that  typhoid  fever  germs  may 
be  carried  by  water  or  milk.  Scarlet  fever  and  other  disease  germs 

248 


OTHER  ENEMIES   OF  THE  BODY  — DISEASE  GERMS      249 


enter  the 
body 


may  be  found  in  milk.  Diphtheria  germs  have  been  found  on 
drinking  cups.  The  germs  are  conveyed  to  these  places  in  some  way 
from  the  bodies  of  persons  sick  with  these  diseases.  The  only 
place  where  the  disease  germs  can  multiply  is  in  the  bodies  of 
the  sick.  You  can  see,  therefore,  why  it  is  of  the  utmost  impor- 
tance that  all  material  coming  from  the  bodies  of  the  sick  should 
be  disinfected  or  destroyed  so  that  the  germs  may  not  be  scattered 
about  to  infect  other  people.  If  this  were  always  done  as  it 
should  be,  do  you  not  think  that  many  diseases  might  be  com- 
pletely stamped  out  in  a  short  time? 

The  germs  of  different  diseases  have  different  methods  of 
getting  into  the  body.  To  know  the  ways  in  which  they  are 
How  most  likely  to  enter  may  help  us  to 

germs  guard  against  them.     Some  may  be 

introduced  by  the  bites  of  insects. 
A  certain  kind  of  mosquito  spreads 

the  germs  of  malaria.   Another  kind  introduces 

into  the  body  with  its  bite  the  germs  of  yel- 
low fever.     Fleas,  carried  by  rats,  spread  the 

germs    of    plague.      Sometimes     pus-forming 

germs  work  their  way  into  the  hair  follicles 

and  sweat  glands  of  the  skin  or  they  get  in 

through  scratches  or  wounds.     The  germs  of 

colds,  tuberculosis,  pneumonia,  influenza,  and 

other  diseases  come  in  through  the  air  pas-    TYPHOID  FEVER  GERMS 

sages.     Typhoid  fever  and  cholera  germs  get 

into  the  body  through  impure  water  and  some- 
times with  the  food,  which  may  be  infected 

by  flies  or  through  being  handled  by  persons 

contaminated  with  typhoid  or  cholera  germs. 

When  the  disease  germs  once  get  a  foothold  in  the  body,  the 

mischief  they  are  able  to  work  is  due  to  two  things :    (i)  the 


ARE  SOMETIMES  CAR- 
RIED ABOUT  AND 
NOURISHED  IN  OTHER- 
WISE CLEAN,  GOOD 
MILK. 


250 


KEEPING  THE  BODY  IN  HEALTH 


great  rapidity  with  which  they  multiply ;  and  (2)  their  power 
to  produce  deadly  poisons. 

You  may  recall  how  the  cells  of  the  body  multiply,  —  by  each 
cell's  dividing  into  two.  Most  disease  germs  multiply  in  the 
same  way,  and,  as  you  already  know,  at  a  very  rapid  rate.  The 
germs  of  cholera,  for  instance,  may  become  full  grown  and  divide 
into  two  in  twenty  minutes.  In  this  way  they  can  extend  their 
ravages  in  the  body  with  great  swiftness. 

The  weapons  used  by  our  germ  enemies  in  their  attacks  upon 
the  body  are  the  deadly  poisons  which  they  produce.  It  is  these 
toxins,  as  they  are  called,  which  are  very  violent  poisons,  that 

really  cause  the  disease  by  poisoning  the 
cells  of  the  body.  Almost  all  fevers  are 
caused  by  these  germ-formed  poisons. 
Some  germs  produce  stupefying  poi- 
sons ;  others,  irritant  poisons ;  still 
others,  paralyzing  poisons.  Each  class 
of  germ  develops  its  own  brand  of 
poison. 

Even  when  a  person  is  in  good 
health,  the  healing  or  restoring  process 
is  constantly  going  on  in  his  body  in 
order  to  keep  him  healthy.  When  one 
has  worked  until  he  is  exhausted,  he 
must  recover  from  his  fatigue  before  he  can  undertake  fresh 
work.  The  digestion  of  a  meal,  for  example,  leaves  the  stomach 
How  the  m  a  congested  state,  from  which  it  must  recover 
body  heals  before  it  is  ready  to  digest  another  meal.  The  body 
itself  is  bemg  continually  worn  by  its  work  and  so  it  needs 

constant  restoring.  This  work  is  done  by  what  we  call  the 
natural  forces  of  the  body ;  that  is,  by  the  power  of  the  body  to 
heal  itself. 


THESE  ARE  DIPHTHERIA  GERMS. 
THEY  MULTIPLY  VERY  RAP- 
IDLY, AND  SO  ARE  LIKELY  TO 
OVERCOME  THEIR  VICTIM  ;  BUT, 
IF  TAKEN  IN  TIME,  DIPH- 
THERIA CAN  BE  CURED. 


OTHER  ENEMIES  OF  THE  BODY  —  DISEASE  GERMS      251 

The  healthy  body  is  able  to  defend  itself  against  germs  in  a 
variety  of  ways.  The  skin  is  an  outer  defense  which  in  a  healthy 
state  cannot  be  penetrated  by  germs.  .  The  mucus  of  the  mouth 
and  nose  has  some  power  to  prevent  the  growth  of  germs  and 
even  to  destroy  them.  The  cells  which  cover  the  lung  surface 
are  constantly  engaged  in  capturing  and  destroying  germs. 
The  gastric  juice  is  a  powerful  germicide,  or  germ  killer, 
capable  of  destroying  the  germs  of  cholera,  typhoid  fever,  and 
any  other  germs  that  are  likely  to  get  into  it.  The  white  cells 
of  the  blood  are  the  special  defenders  of  the  body  against 
germs  that  enter  the  tissues,  and  the  plasma,  or  serum,  also 
has  power  to  destroy  germs. 

When,  through  the  weakening  of  the  natural  defenses,  the 
germs  are  able  to  gain  a  foothold  in  the  body,  great  injury  may 
be  done.  The  germ  poisons  irritate  or  paralyze  the  tissues, 
and  cause  inflammation,  congestion,  pain,  and  other  disturb- 
ances. The  body  must  then  make  a  special  effort  to  do  the 
healing,  and  it  has  to  rally  all  its  forces  to  meet  and  conquer 
the  invading  army.  This  it  does  in  two  ways :  (i)  by  increasing 
the  number  of  white  cells ;  (2)  by  the  formation  of  special  germ- 
killing  substances  in  the  blood  called  antitoxins  to  act  against  the 
toxins  made  by  the  disease  germs. 

You  remember  how  the  white  cells  in  the  blood  seem  to  be 
attracted  to  the  germs  that  get  into  the  body  and  how  they 
inclose  or  swallow  them.  Then  ensues  a  struggle  in  which  the 
germ  tries  to  kill  the  corpuscle,  and  the  corpuscle  tries  to  digest 
and  kill  the  germ.  The  life  of  the  person  in  whom  this  fight 
is  going  on  depends  upon  which  wins  the  victory,  the  corpuscles 
or  the  germs.  All  that  the  doctor  or  nurse  can  do  is  to  help 
the  body  to  summon  all  its  natural  forces,  and  to  try  as  far  as 
possible  to  assist  the  little  soldiers  in  their  fight. 

As  each  class  of  germs  has  its  own  particular  poison,  so  the 


252 


KEEPING  THE  BODY  IN  HEALTH 


body  produces  a  special  germ-killing  substance  suited  to  the 
particular  kind  of  germ  by  which  it  is  being  attacked.  You 
know  there  are  diseases,  such  as  smallpox  and  scarlet  fever, 
which  a  person  usually  has  but  once.  A  person  who  has  had 
smallpox  may  afterward  go  among  people  suffering  with  this 
disease  without  any  danger  of  infection.  He  has  become  im- 
mune to  that  disease;  that  is,  that  particular  kind  of  disease 
germ  can  no  longer  grow  and  multiply  in  his  body.  The  reason 
for  this  seems  to  be  that  the  special  substance  required  to  kill 
that  kind  of  germ  remains  in  his  blood  through  life  and  promptly 
kills  any  such  germs  that  may  enter.  Some  diseases  we  may 
have  again  and  again,  because  the  germ-killing  substance  for 
those  particular  germs  quickly  passes  out  of  the  blood. 

Since  we  are  in  constant  danger  of  attack  from  disease  germs, 

it  is  necessary  to  be  constantly 
on  guard  against  them.    What 
are  some  of  the  ways  Guarding 
in  which  we  may  be  against 
protected    from    at-  disease 
tacks  of  this  sort  ?     In  the  first 
place,  by  means  of  public  hy- 
giene or  sanitation  we  may  pro- 
tect ourselves.    The  health  and 
sanitary  officers  in  a  commu- 
nity may  be  looked  upon  as  a 

HERE  ,s  A  DROP  OF  WATER  CREATE  MAG-    f°rt  °f  advance  guard  or  SCOUt- 
NIFIED  SHOWING  ORGANISMS,  STILL  MORE    ing  party.    They  go  out,  armed 

HIGHLY    MAGNIFIED,    THAT    MIGHT    CAUSE  .,,  ,  , 

'  DISEASE  IF  ONE    SHOULD   DRINK   THE    with  microscope  and  test  tube, 

WATER.      SUCH    WATER   IS     NOT     SAFE     TO      t()      gpy      Qut      fae       enemV,  tO 

DRINK   WITHOUT   LONG   BOILING.  r  J     .  J  ' 

find    out    where    the    disease 

germs  may  be  lurking  and  from  what  point  they  are  likely  to 
make  their  attack.  If  possible,  they  destroy  them  before  they 


OTHER  ENEMIES  OF  THE  BODY  —  DISEASE  GERMS      253 

have  a  chance  to  do  any  mischief.  When  this  is  not  possible, 
they  warn  people  so  that  they  may  be  on  their  guard.  They 
compel  people  to  put  a  large  placard  on  a  house  when  any 
one  inside  is  sick  from  an  infectious  disease.  They  examine 
the  drinking  water  and  see  that  there  is  a  pure  supply  or  that 
people  are  warned  when  their  supply  contains  disease  germs 
or  parasites.  They  inspect  the  food  supplies  in  the  markets 
and  stores  and  order  any  that  are  unfit  for  food  to  be  promptly 
destroyed.  When  there  is  an  outbreak  of  disease  in  a  com- 
munity, they  search  out  the  cause  and  see  that  it  is  corrected. 

In  the  World  War  special  attention  was  given  to  sanitation. 
Officers  were  always  sent  out  in  advance  with  the  army 
scouts.  They  tested  all  the  wells  and  labeled  them  so  that  the 
soldiers  would  know  if  the  water  was  fit  for  drinking.  They 
went  with  the  foraging  parties  and  sampled  all  the  food,  fruit, 
and  vegetables  sold  along  the  line  of  march.  They  examined 
the  sanitary  conditions  of  every  town  before  the  army  arrived. 
If  there  was  any  danger  from  infection,  the  place  was  quaran- 
tined and  guarded.  In  the  camps,  they  taught  the  soldiers 
how  to  protect  themselves. 

As  the  result  of  this  careful  attention  to  sanitary  conditions 
the  percentage  of  soldiers  that  suffered  or  died  from  camp  dis- 
eases was  smaller  than  ever  before  in  a  great  war.  Typhoid  fever 
was  almost  unknown  among  American  soldiers,  whereas  in  the 
Spanish-American  War,  the  death  rate  from  preventable  disease 
was  70  per  cent,  —  only  268  men  were  killed  by  bullets,  while 
3862  died  in  the  hospitals.  This  will  give  you  some  idea  of  how 
much  may  be  done  by  public  hygiene  to  guard  people  from 
disease. 

As  we  have  public  hygiene,  so  we  must  have  domestic  hygiene. 
You  will  recall  that  house  dust  is  very  dangerous.  It  contains 
germs  brought  in  from  the  street  on  the  feet,  or  that  have  floated 


254  KEEPING  THE  BODY  IN  HEALTH 

in  the  air,  particularly  those  of  pneumonia  and  tuberculosis,  two 
of  the  most  dangerous  of  communicable  diseases.  Sweeping  and 
Domestic  dusting  are  sometimes  done  in  a  way  that  only  stirs 
hygiene  Up  germs,  and  keeps  them  floating  about,  instead  of 
getting  rid  of  them.  The  vacuum  cleaner,  which  sucks  up  all  the 
dust  and  scatters  none  of  it,  is  by  far  the  best  method  of  re- 
moving dust  from  curtains  and  carpets.  The  dustless  duster 
or  a  damp  cloth  will  remove  the  dust  which  the  ordinary  dry 
duster  only  stirs  up. 

The  kitchen,  pantry,  sinks,  closets,  and  cellars  need  frequent 
cleaning.  Fermenting  and  decaying  materials  are  always  a 
source  of  germs,  and  they  should  not  be  allowed  to  accumulate. 
Cesspools  should  be  situated  far  from  the  house  and  should  be 
water-tight  so  that  the  soil  about  the  house  cannot  become 
polluted  with  drainage.  Stables  and  animal  pens  should  be  at  a 
distance  from  the  house  and  should  be  kept  clean. 

Sunlight  is  Nature's  great  disinfectant.  It  destroys  germs 
brought  in  contact  with  it.  So  we  should  admit  the  sunlight 
to  every  room  in  the  house,  closets  included,  if  possible.  Let 
sunlight  do  its  disinfecting  work  in  every  nook  and  corner  of  the 
home.  Fire  is  the  best  of  all  disinfectants.  Germ-producing 
matter  should  be  burned  whenever  possible.  Ordinary  boiling, 
continued  for  half  an  hour,  will  destroy  many  kinds  of 
dangerous  germs. 

Of  more  importance  to  the  individual  than  either  public  or 
domestic  hygiene  is  personal  hygiene  —  the  acquiring  of  those 
Personal  habits  which  will  keep  the  germs  out  of  the  body 
hygiene  anc[  WJH  keep  up  the  natural  power  of  the  body  to  kill 
them  if  they  should  enter. 

Mention  some  personal  habits  which  may  be  a  means  of  in- 
troducing germs  into  the  body.  Think  of  the  ways  in  which  the 
hands  may  gather  germs  in  the  course  of  a  day,  —  from  door 


OTHER  ENEMIES  OF  THE  BODY  —  DISEASE  GERMS      255 

knobs,  car  straps,  money,  and  the  hands  of  other  persons.  Should 
there  be  disease  germs  upon  them,  these  may  get  into  the  mouth 
with  the  food  or  into  the  eyes  if  the  eyes  are  rubbed.  The  sim- 
plest and  easiest  method  of  disinfecting  the  hands  is  by  a  thorough 
washing  with  soap.  This  is  especially  necessary  before  eating. 
Drinking  from  a  cup  used  by  others  is  another  way  by  which 
disease  germs  may  get  into  the  body.  At  school  or  when  travel- 
ing one  should  always  carry  a  private  cup.  Avoid  putting  into 
the  mouth  pencils,  money,  or  other  articles  that  have  been 
handled  by  others. 

Among  other  things  it  is  important  to  remember  that  common 
colds  are  really  infectious;  so  when  one  says,  "I  have  caught  a 
cold,"  he  really  has  in  fact  been  infected  through  contact  with 
some  other  person  who  has  a  cold,  just  as  he  might  have  con- 
tracted smallpox  by  meeting  a  person  suffering  from  this  disease. 
We  catch  colds  from  people  who  have  colds,  not  from  the  weather. 
It  is  true  that  one  may  contract  a  cold  without  having  come  in 
contact  with  another  person  suffering  from  an  acute  cold,  for  the 
reason  that  many  persons  who  are  subject  to  colds  are  "cold 
carriers";  that  is,  they  always  carry  in  the  nose  or  throat  the 
particular  germs  which  give  rise  to  colds,  and  if  they  happen  to 
lower  their  resistance  a  little  by  loss  of  sleep,  by  breathing  impure 
air,  by  becoming  overheated  or  greatly  fatigued,  by  getting 
chilled,  by  becoming  constipated,  by  overeating,  especially  of 
meat  or  rich  foods,  —  in  any  of  these  conditions,  the  germs 
take  advantage  of  the  lowered  resistance  of  the  body,  rapidly 
multiply,  and  produce  the  poisons  which  cause  the  fever  and  other 
discomforts  which  accompany  the  cold. 

It  is  important  to  avoid  any  person  suffering  from  an  acute 
cold.  Do  not  stay  near  a  person  who  is  coughing  or  sneezing 
or  who  is  making  use  of  a  soiled  handkerchief.  Such  persons 
are  in  a  highly  infectious  condition. 


POSTURE  AND 
TUBERCULOSIS 


Poor  posture  encourages  tuberculosis. 
Erect  carriage  combats  it. 

Right  poslure  aquired  in  childhood  promotes 
Strong, healthy  lungs 
Good  Circulation 
Sound  health 
Proper  growth  and  development. 

Train  the  child  in  right  posture 
not  by  constant  nagging,  but  by 
suitable  exercise,  instruction 
in  hygiene  and  a  good  example 


ONA.TIONAL  CHILD  WElfAflf  ASSOCIATION,  HI  W  YOR 
NATt.  ASJN.  rOH.  TH{  5THPY  ANO*rn.lVt *NT1ON  Of  niKHtClHO 


OTHER  ENEMIES  OF  THE  BODY  —  DISEASE  GERMS     257 

One  who  has  a  cold  should  also  take  care  to  protect  others  by 
avoiding  close  contact  with  them,  by  holding  a  handkerchief  over 
the  mouth  when  coughing  or  sneezing,  and  by  taking  great  care 
to  avoid  infecting  books,  door  knobs,  or  anything  else  which 
others  may  need  to  handle. 

Even  with  all  the  precautions  that  we  have  mentioned,  it  is 
not  possible  to  keep  the  body  entirely  free  from  disease  germs. 
There  are  usually  present  in  the  body  germs  capable  of  Keeping  up 
producing  disease,  waiting  for  a  favorable  opportunity  body 
to  attack.  These  are  not  to  be  feared  so  long  as  the  resistance 
body  is  in  such  a  healthy  condition  that  its  natural  defenses  are 
active.  But  to  let  the  body  get  run  down  or  weakened  by  bad 
habits  is  to  open  the  gates  to  the  enemy.  This  may  be  done  by 
lack  of  exercise,  bad  food,  overeating,  insufficient  sleep,  bad  ven- 
tilation, overwork,  or  by  the  use  of  alcohol.  Show  why,  in  each 
case. 

When  one  country  is  expecting  war  with  another  the  standing 
army  is  carefully  inspected  to  see  that  all  its  soldiers  are  well 
equipped  and  in  good  fighting  trim.  Care  is  also  taken  that  the 
reserve  forces  shall  be  ready  if  called  upon.  It  is  just  as  im- 
portant for  us,  subject  as  we  are  to  the  attacks  of  germs,  to  keep 
our  standing  army  of  body  defenders  in  good  condition  and  our 
reserve  forces  ready  to  be  drawn  upon  if  necessary. 

HEALTH  PROBLEMS 

1.  What  is  the  meaning  of  the  natural  defenses  of  the  body  ?    Is  the 
term  "natural  defenses"  appropriate?    Why?    Mention  some  of  these 
natural  defenses. 

2.  How  do  nurses  and  doctors  generally  avoid  taking  diseases  from  the 
sick  persons  whom  they  treat  ? 

3.  In  some  cities  there  are  bungalows  on  the  roofs  of  skyscrapers.    The 
people  who  build  these  plan  to  live  in  them  just  as  other  people  live  in 
houses  built  on  the  ground.    If  you  were  living  in  Chicago  or  New  York 


258  KEEPING  THE  BODY  IN  HEALTH 

or  any  other  large  city,  do  you  think  it  would  be  more  healthful  to  live  in 
one  of  these  bungalows  than  in  the  ordinary  house  ?    Why  ? 

4.  Suppose  some  one  member  of  the  family  is  always  catching  colds 
and  coughs,  what  may  be  the  explanation  of  this?    How  should  such  a 
person  be  treated  ? 

5.  If  you  were  living  in  a  malarial  country,  what  gateway  of  germs 
to  the  body  would  you  guard  particularly  ?    Why  ? 

6.  Suppose  there  was  an  epidemic  of  yellow  fever  in  your  community, 
what  gateway  to  the  body  would  you  guard  particularly?    Why?     Con- 
sider in  the  same  way  an  epidemic  of  typhoid  fever  and  of  diphtheria. 

7.  Give  an  instance  of  the  power  of  the  body  to  heal  itself  from  some 
severe  injury  or  illness. 

8.  You  often  hear  a  person  say:    "I  was  all  run  down,  and  I  caught  a 
cold."    Just  what  does  he  mean  by  this?    Do  people  catch  coughs  and 
colds  more  frequently  when  they  are  "run  down"  than  at  other  times? 
Why? 

9.  Speak  of  habits  you  observe  in  people  which  are  likely  to  weaken 
their  "natural  defenses."    Are  such  persons  often  ill?    Why? 

10.  Show  how  the  sanitary  officers  in  a  community  are  much  like  the 
scouts  and  pickets  in  an  army.  Suppose  the  scouts  and  pickets  should 
not  do  their  duty,  what  might  happen  to  the  army  ?  Might  it  be  the  same 
way  in  a  community  if  sanitary  officers  were  neglectful  of  their  duty? 

REVIEW  QUESTIONS 

1.  When  are  germs  likely  to  get  a  foothold  in  the  body? 

2.  What  are  the  names  used  for  disease  germs? 

3.  How  may  the  germs  of  tuberculosis  be  spread?    The  germs  of 
typhoid?    Of  diphtheria ? 

4.  Where  are  the  breeding  grounds  for  germs  that  cause  sickness  ? 

5.  How  do  insects  spread  disease? 

6.  How  do  the  germs  of  colds,  influenza,  and  other  diseases  get  into 
the  body? 

7.  In  what  ways  do  germs  harm  the  body? 

8.  How  do  disease  germs  multiply?    How  rapidly  do  the  germs  of 
cholera  multiply  ? 

9.  What  is  the  meaning  of  toxins  ? 

10.  How  does  the  body  defend  itself  against  its  germ  enemies? 


OTHER  ENEMIES  OF  THE  BODY  —  DISEASE  GERMS*     259 

1 1 .  What  has  Nature  provided  in  the  body  to  kill  disease  germs  ?    How 
do  the  poisons  made  by  the  germs  work  upon  the  body  ? 

12.  What  are  the  chief  defenders  of  the  body  against  disease  germs? 

13.  What  do  the  corpuscles  and  antitoxins  do  to  help  the  body  in  its 
fight  against  germs  ? 

14.  What  does  it  mean  to  become  immune  to  a  disease?    Why  does  a 
person  have  smallpox  only  once  in  a  lifetime  ? 

15.  What  are  the  means  of  guarding  against  germ  enemies? 

1 6.  What  precautions  were  taken  to  protect  our  soldiers  against  germ 
enemies  in  the  late  war? 

17.  What  are  some  of  the  ways  in  domestic  hygiene  for  guarding  against 
disease  germs  ? 

18.  Mention  several  good  ways  to  kill  germs. 

19.  What  is  meant  by  personal  hygiene  ? 

20.  Mention  some  habits  of  life  which  will  enable  one  to  fight  disease 
germs  successfully. 

21.  What  does  it  mean  to  "open  the  gates  to  the  body's  enemies" ? 


CHAPTER  XX 

"CATCHING"  DISEASES 

No  person  would  purposely  plan  to  make  a  friend  sick.  Yet 
it  often  occurs  that  unintentionally  one  who  is  ill,  by  merely 
going  among  other  persons,  causes  others  to  become 
The  dan-  [\\  too  This  is  because  the  disease  he  has  is  communi- 
conta  ious  ca^e^  or  can  ^e  Passed  from  one  person  to  another, 
diseases  In  other  words,  it  is  a  " catching"  or  contagious  disease. 
Smallpox,  measles,  scarlet  fever,  diphtheria,  chicken 
pox,  mumps,  and  whooping  cough  are  all  communicable  or  con- 
tagious diseases.  A  child  who  has  any  one  of  these  is  a  danger 
to  other  children  until  he  is  entirely  well,  even  though  he  himself 
may  not  feel  sick.  Very  severe  cases  often  result  from  coming 
in  contact  with  one  of  these  diseases  in  a  mild  form. 

Those  who  guard  the  health  of  the  people  have  made  it  a  law 
that  persons  having  a  communicable  disease  shall,  as  soon  as 
Quaran-  this  is  known,  live  quite  apart  from  other  people.  A 
tine  person  who  is  compelled  to  live  thus  apart  from  others 

is  said  to  be  in  quarantine.  This  precaution  is  necessary  in  order 
to  prevent  others  from  taking  the  same  disease  and  is  a  most  im- 
portant sanitary  regulation.  With  many  children,  quarantine  is 
the  hardest  part  of  the  illness,  since  they  must  stay  at  home,  and 
none  of  their  playmates  may  come  to  see  them.  But  when  one 
thinks  of  the  risk  to  others,  it  seems  quite  right  that  a  strict  quar- 
antine should  be  enforced  in  all  cases  of  infectious  diseases. 

My  young  friend  Georgia,  at  school  one  day,  complained  of 
having  a  sore  throat.  Her  teacher  at  once  sent  her  home, 
although  the  girl  said  she  did  not  really  feel  sick,  and  begged 

260 


"CATCHING"  DISEASES 


261 


to  be  allowed  to  remain.  The  teacher  did  not  send  her  away  be- 
cause of  her  misfortune  in  having  a  sore  throat,  but  as  a  precau- 
tion for  the  rest  of  the  pupils.  Did  the  teacher  do  the  right 
thing  in  sending  Georgia  home  ? 

The  teacher  knew  that  sore  throat  is  often  a  danger  signal, 
and  such  it  proved  to  be  in  Georgia's  case.     Soon  after  reaching 
home,  she  began  to  feel  hot  and  feverish;  and  her  How  a 
mother  called  a  physician.     When  the  physician  dis-  culture 
covered  that  her  throat  was  sore,  he  took  a  small  is  taken 
wooden  stick  from  his  case.     Around  one  end  of  this  he  wound 
some  sterile  cotton,  that 
is,    cotton   free   from   all 
germs,  and  made  a  swab. 
With  the  swab  he  wiped 
the    little    girl's    throat. 
Afterward     he    put    the 
substance   wiped    off   on 
the    kind    of    soil    upon 
which  germs  like  best  to 
grow,  —  that  is,  upon  a 
"  culture"  plate.     If 
Georgia   had   diphtheria 
as  the  doctor  feared,  this 

culture       would,    he    GEORGIA  COMPLAINED  ONE  DAY  IN  SCHOOL  OF  A 

kneW,      ShoW     it     in     a     feW  HEADACHE   AND   SORE   THROAT   AND   THE   TEACHER 

SENT  HER  HOME  IMMEDIATELY.      WHY? 

hours.  Diphtheria  is  al- 
ways caused  by  germs.  These  germs  grow  on  the  mucous 
membrane  of  the  mouth  and  throat.  They  are  so  tiny  they 
cannot  be  seen  with  the  eye  alone.  But  if  some  of  them  are 
wiped  off,  and  planted  on  " culture"  soil,  a  microscope  will  re- 
veal them  as  they  grow.  If  the  throat  from  which  the  culture 
is  taken  has  no  diphtheria  germs,  this, 'too,  will  be  shown. 


262  KEEPING  THE  BODY  IN  HEALTH 

The  doctor  told  Georgia's  mother  that  until  he  could  make  a 
report  on  the  case,  it  would  be  safer  to  put  Georgia  in  a  room 
as  remote  as  possible  from  those  occupied  by  other  people,  and 
to  take  out  of  it  all  but  necessary  furniture.  When  Georgia's 
father  built  their  cottage,  he  made  one  room  in  the  upper  story 
that  opened  upon  a  covered  porch.  It  was  also  connected  with 
a  small  bathroom.  There  were  three  nice  windows,  too,  so  that 
there  could  be  plenty  of  sunshine  and  fresh  air.  The  room  was 
at  the  end  of  a  hall,  and  the  family  called  it  their  "  hospital 
corner,"  because  in  times  of  illness  it  made  a  very  satisfactory 
sick  room. 

Georgia  was  put  in  this  room  for  the  night,  after  her  mother 
had  taken  out  all  the  extra  things.  In  the  morning,  the  culture 
taken  from  her  throat  showed  that  Georgia  had  diphtheria. 
The  doctor  said  she  must  not  go  from  the  "hospital  corner"  to 
any  other  part  of  the  house,  and  that  no  one  but  the  nurse  and 
himself  could  be  allowed  in  the  room  with  her.  To  prevent  the 
risk  of  any  other  child's  entering  the  room  unawares,  the  nurse 
kept  the  door  locked. 

Diphtheria  is  a  very  " catching"  disease.  Now  that  it  was 
certain  diphtheria  germs  were  making  Georgia  ill,  the  doctor 
Antitoxins  sa^  that  sne  an<^  everv  one  m  the  house  should  have 
and  their  a  dose  of  antitoxin  (anil  means  opposed  to,  and  toxin, 
use  poison) ,  a  remedy  that  works  against  the  poison  which 

diphtheria  germs  always  make  in  the  body.  Have  you  heard  this 
term  before  ? 

It  is  only  within  recent  years  that  it  has  been  possible  to 
secure  this  remedy.  Before  its  use,  only  about  one  half  of  those 
who  had  the  disease  in  severe  form  got  well.  But  now  thousands 
of  lives  are  saved  by  the  employment  of  this  antitoxin.  The  more 
promptly  it  is  given,  the  better  the  results.  Where  it  is  used 
within  the  first  twenty-four  hours  of  illness,  there  is  a  loss  of 


"CATCHING"  DISEASES  263 

only  one  life  in  a  thousand  cases.  Do  you  not  think  that  every- 
one should  make  use  of  this  antitoxin  when  he  is  is  in  any  danger 
from  diphtheria  ? 

It  happens  quite  often  that  a  person  having  diphtheria  germs, 
although  not  at  all  sick  himself,  gives  the  disease  to  others.  Such 
a  person  is  called  a  carrier,  and  the  health  of  every  one  with  whom 
he  comes  in  contact  is  in  danger  so  long  as  he  has  the  germs.  His 
own  body  makes  enough  antitoxin  to  defend  itself,  but  that  does 
not  mean  safety  for  other  people.  In  some  cities,  when  a  case 
of  diphtheria  occurs  in  a  school,  cultures  are  taken  from  the 
throats  of  all  persons  who  are  in  the  same  classroom  with  the 
patient  in  order  to  find  who  the  carrier  may  be.  Carriers  need 
to  be  quarantined  and  to  have  the  germs  in  their  throats 
destroyed,  just  as  in  the  case  of  a  person  who  is  actually  sick 
with  the  disease. 

In  the  case  of  Georgia,  the  health  officers  had  been  notified 
of  her  illness,  and  a  red  placard  was  put  on  the  door,  warning 
all  who  came  that  way  not  to  enter.     Why  ?    A  notice  Pfe 
was  placed  where  the  milkman  could  see  it  telling  him  cautions 
not  to  leave  bottles  but  to  pour  the  milk  into  a  dish  observed 
placed  especially  for  him.     Why?     A  poster  placed  !?quai 
indoors  gave  directions  to  the  family  as  to  how  they 
must  care  for  themselves  and  for  the  diphtheria  patient. 

Some  of  the  things  it  said  were : 

"Diphtheria  is  always  dangerous  and  easily  given  to  others.  It  is 
catching  from  the  mildest  form.  Those  not  sick  enough  to  be  in  bed  give 
the  disease  to  others  oftener  than  the  very  sick. 

"Diphtheria  patients  must  not  leave  the  house  until  th?  Department 
of  Health  removes  the  warning  card.  Neither  may  people  living  in  the 
house  go  in  and  out.  Inmates  of  the  house  must  stay  indoors. 

"Visitors  are  not  allowed. 

"Groceries  and  milk  must  be  left  at  the  door. 

"School  children  and  others  must  stay  at  home.    No  one  living  in  the 


264 


KEEPING  THE  BODY  IN  HEALTH 


house  is  allowed  to  go   to   church,  Sunday  school,  or  to  other  public 
places. 

"Do  not  let  the  patient  spit  on  the  floor. 

"Spit  and  nose  discharges  will  give  the  disease  to  others,  and  should  be 
caught  on  cloths,  and  burned  immediately. 
"Do  not  kiss  the  patient. 

"After  touching  the  patient  or  anything  he  handles,  always  wash  your 
hands. 

"Everything, — letters,   laundry,   bedding,   books,   magazines,   papers, 
and  clothing  must  be  disinfected  before  they  are  taken  out  of  the  house. 

"Everything  used  in  the 
sick  room,  such  as  knives, 
forks,  spoons,  dishes,  books, 
playthings,  handkerchiefs,  tow- 
els, sheets,  pillow  slips,  cloth- 
ing, flowers,  and  remnants  of 
food  must  be  disinfected  before 
being  taken  from  the  room." 

To  disinfect  an  article, 
you  will  remember,  means 
to  do  something  to  the 
article  that  will  kill  all  the 
germs  on  it.  Any  article 
which  will  not  be  harmed 
by  boiling  may  be  disin- 
fected in  that  way.  So 
on  a  gas  plate  in  the  bath- 
room, Georgia's  nurse  kept 

EVERYTHING  A  PATIENT  SUFFERING  FROM  AN  IN-         ,•      um']pr   f^i]    of 

FECTIOUS   DISEASE   USES   OR  TOUCHES  SHOULD  BE 

DISINFECTED,    BY   BOILING    IF    POSSIBLE,    BEFORE      JUSt    at    tllC    boiling 

ANYONE  ELSE  IS  ALLOWED  TO  USE  OR  TOUCH  IT.  .  ,,       .  ,.    , 

All  the  dishes  and  every- 
thing which  Georgia  used  or  touched  were,  as  soon  as  she  was 
through  with  them,  put  into  this  water,  and  boiled  for  twenty 
minutes.  When  boiling  is  not  convenient/ a  metal  tub  may  be 


"CATCHING"  DISEASES  265 

filled  with  a  solution  which  the  doctor  will  order,  and  all  articles 
may  be  soaked  in  it  for  sufficient  time  to  make  them  sterile. 

One  thing  is  to  be  especially  remembered  whenever  a  person 
has  a  communicable  disease :  Nothing  must  ever  be  allowed  to 
leave  the  sick  room  until  the  germs  on  it  have  been  killed  by  thorough 
disinfection. 

Georgia's  father  constructed  a  very  good  kind  of  dumb  waiter 
by  means  of  which  meals  might  be  sent  up  to  the  sick  room. 
First,  he  attached  a  small  chain  to  a  large  tin  bread  box.  Then 
by  fastening  a  pulley  to  the  porch  railing  and  adjusting  the  chain 
on  it,  the  box  could  be  raised  and  lowered  with  ease.  The  nurse 
opened  the  box  on  the  porch  outside  the  door  and  emptied  all  foods 
into  the  special  dishes  kept  there  for  Georgia's  use  and  her  own. 
Then  she  told  the  one  below  to  lower  the  box.  The  nurse  was 
always  careful  to  disinfect  her  hands  before  touching  the  box  or 
its  contents,  so  that  not  a  germ  might  find  its  way  to  the  rooms 
below. 

The  doctor  was  quite  at  a  loss  to  know  where  Georgia  could 
have  got  diphtheria  germs,  as  no  " carriers"  had  been  found. 
There  was  not  a  case  in  that   town,    and  there  had  How  the 
been  none  for  a  long   time.     Neither   had    Georgia  disease 

been  away  on  any  visits. 

Avcrc 

"  Isn't  it  odd  that  my  Cousin  Ellen  should  be  having  carried  in 
the  same  disease  that  I  am?"  said  Georgia  one  morning  Georgia's 
during  the  doctor's  visit.  case 

" Where  does  your  cousin  live?"  inquired  the  doctor. 

"  'Way  up  in  Canada,"  replied  the  little  girl. 

"Then  how  do  you  know  she  has  been  sick?" 

"Oh,  we  write  letters  to  each  other.  She  wrote  me  that  she 
was  having  to  stay  out  of  school  because  she  had  been  ill  with 
diphtheria.  It  is  queer  that  the  same  thing  has  happened  to 
both  of  us." 


266  KEEPING  THE  BODY  IN  HEALTH 

"How  long  is  it  since  you  got  that  letter?" 

"Oh,  about  two  weeks,"  replied  Georgia. 

"Well,"  said  the  doctor,  "it  does  not  seem  at  all  queer  to  me. 
It  is  plain  enough  now  that  the  germs  which  are  causing  you  so 
much  unpleasantness  came  to  you  sealed  up  in  your  cousin's 
letter.  The  strange  thing  is  that  her  people  should  permit  her 
to  send  letters  while  she  was  ill  with  a  'catching'  disease." 

"I  guess,  perhaps,  they  didn't  know  about  it,"  said  Georgia, 
"for  Cousin  Ellen  wrote  us  that  they  would  not  let  her  go  out 
at  all,  so  she  was  going  to  drop  her  letter  out  of  the  window  and 
ask  the  neighbor  girl  to  post  it." 

"It  would  not  surprise  me  if  the  neighbor  girl,  too,  took  diph- 
theria from  that  letter,"  said  the  doctor.  "Diphtheria  germs 
pass  from  the  sick  to  the  well  so  easily  that  everything  touched 
by  the  patient  is  dangerous  until  the  germs  on  it  are  killed ;  and 
these  germs  live  a  long  time. 

"  A  little  boy  I  knew  died  from  diphtheria.  His  mother,  out 
of  fondness  for  him,  kept  his  picture  blocks  and  books  and  toys 
in  a  trunk  which  she  stowed  away  in  the  attic.  Years 
and  play-  afterward,  some  other  little  children  playing  in  the  attic 
things  found  these  playthings,  and  from  them  got  the  germs 
may  carry  that  made  both  of  them  very  ill  with  diphtheria, 
germs  These  facts  and  many  similar  ones  have  made  it  plain 
that  the  greatest  care  must  be  taken  with  regard  to  all  the  things 
that  come  into  contact  with  those  who  are  ill  with  diphtheria. 
The  same  is  true  in  respect  to  other  i  catching '  diseases.  So  you 
see  it  is  better  always  to  do  exactly  what  the  health  boards  and 
those  who  make  a  study  of  these  diseases  tell  us,  even  though  it 
is  not  very  pleasant  at  the  time.  " 

"May  I  have  my  dolly  to  play  with,  while  I  am  in  quaran- 
tine?" asked  Georgia. 

"You  may  have  anything  you  want  provided  you  are  willing 


"CATCHING"  DISEASES  267 

that  it  should  be  burned  when  you  get  well,"  replied  the 
doctor. 

"Oh,  when  shall  I  be  well,  then?"  she  continued. 

"When  the  cultures  from  your  throat  show  that  you  no  longer 
have  diphtheria  germs,"  was  the  doctor's  answer.  "No  one  can 
tell  just  how  long  that  may  be,  but  you  can  help  things  along 
by  cheerfully  taking  your  treatments  and  doing  as  your  nurse 
tells  you." 

"And  does  everything  I  play  with  have  to  be  burned?"  she 
asked  again. 

"Anything  that  can  be  boiled  without  harm  can  be  saved," 
said  the  doctor.  "There  are  other  ways  in  which  some  things 
can  be  made  safe,  but  in  general  it  will  be  wiser  to  bring  nothing 
up  here  that  you  will  afterward  need  or  care  especially  for.  Your 
nurse  knows  so  many  nice  things  to  do,  you  will  not  miss  your 
dolly,  I  am  sure." 

Just  then  the  barking  of  a  dog  below  called  Georgia's  attention 
to  her  pet,  and  she  asked,  "Why  doesn't  somebody  open  the  door 
for  Gyp?" 

"Gyp  is  in  quarantine,  too,"  said  the  doctor.  "He  lives  in 
the  carriage  house  now.  It  would  be  unsafe  to  allow  him  in  the 
house  while  there  are  diphtheria  germs  about.  Animals  as  well 
as  human  beings  take  the  disease.  Even  if  Gyp  did  not  catch 
it  himself,  he  might  be  the  means  of  giving  it  to  some  person, 
for  the  germs  might  get  in  his  hair,  and  he  would  scatter  them 
wherever  he  went.  He  is  made  quite  comfortable  and  has 
plenty  to  eat,  but  he  doesn't  like  to  be  shut  out  any  better  than 
you  like  to  be  shut  in." 

Every  day  a  cot  was  placed  in  a  quiet  corner  of  the  porch.  On 
it  Georgia  was  allowed  to  lie  out  of  doors  where  she  could  watch 
all  that  was  going  on  around  her  and  breathe  the  fresh  air. 

When  she  was  able  to  sit  up,  a  large  shallow  pan  of  sand  placed 


268 


KEEPING  THE  BODY  IN  HEALTH 


on  a  bedside  table  afforded  her  many  pleasant  hours  of  play. 
Out  of  it  she  made  a  farm  with  valleys  and  hills,  rivers,  and  lakes. 
For  trees  she  planted  green  twigs.  A  cardboard  house  and  barns, 
fences  of  toothpicks,  and  paper  men,  women,  children,  and  ani- 
mals made  it  seem  quite  real. 

At  other  times  the  sand  pan  was  an  athletic  field  where  paper 
boys  played  ball,  or  it  was  a  park  with  flower  beds  and  winding 


GEORGIA  WILL  RECOVER  RAPIDLY,  SINCE  SHE  SPENDS  MOST  OF  EVERY  DAY  OUT  IN  THE  FRESH 
AIR  AND  SUNSHINE  J  AND  SHE  IS  KEPT  PLEASANTLY  OCCUPIED. 

paths,  with  cages  of  wild  animals.  Again  it  became  a  model  town 
with  broad  streets,  on  which  paper  automobiles  and  trolley  cars 
were  seen.  So  many  and  varied  were  the  things  that  could  be 
made  with  that  sand  pan  that  Georgia  quite  forgot  she  was  in 
quarantine  ;  and  she  was  really  a  little  bit  sorry  when  one-morn- 
ing the  doctor  said  to  her,  "You  have  a  clean  throat,  and  to- 


"CATCHING"  DISEASES  269 

day,  when  your  nurse  has  given  you  a  cleansing  bath  all  over, 
including  your  hair,  you  may  put  on  clean  clothing  and  go 
down  stairs." 

"May  I  go  to  school  to-morrow?"  she  asked. 

"Not  to-morrow,  but  in  a  few  days,"  was  the  answer.  "Cul- 
ture tests  must  be  made  again.  The  house,  too,  must  first  be 
cleansed  of  germs  so  that  you  will  carry  none  to  school." 

Years  ago  people  understood  little  about  germs,  and  their 
part  in  the  cause  of  diseases.  They  knew  that  certain  diseases 
were  "catching,"  and  that  these  rarely  attacked  the  same  in- 
dividual twice.  It  was  a  common  belief  that  everybody  must 
have  measles,  scarlet  fever,  whooping  cough,  chicken  pox,  and 
mumps,  and  that  the  earlier  in  life  each  person  took  his  turn  the 
better  it  would  be  for  him.  Little  care  was  taken  to  avoid 
diseases,  and  sometimes  children  were  sent  to  visit  the  sick  in 
order  to  catch  the  disease.  I  suppose  you  do  not  need  to  be 
told  that  very  many  lives  were  lost  through  such  ignorance. 

HEALTH  PROBLEMS 

1.  Are  pupils  ever  kept  out  of  your  school  on  account  of  illness?    Who 
forbids  them  to  come  to  school  ? 

2.  Have  you  known  pupils  who  have  come  to  school  with  contagious 
diseases  and  have  given  them  to  other  pupils?  .    Was  this  fair  to  the  well 
pupils  ? 

3.  Have  you  been  vaccinated  ?    What  good  does  vaccination  do  ? 

4.  Have  you  known  any  person  who  has  been  given  antitoxin?      If 
so,  what  was  the  reason  that  it  was  given  to  him?     Did  it  help  him? 

5.  Find  out  how  antitoxin  is  prepared.    Your  family  physician  should 
be  able  to  tell  you. 

6.  If  two  people  are  exposed  to  diphtheria  in  the  same  way,  one  may 
catch  it  and  the  other  may  not.     Explain. 

7.  Is  there  a  medical  inspector  or  visiting  nurse  who  visits  your  school? 
If  so,  state  just  what  he  or  she  does.    If  there  is  no  such  inspector,  do  you 
think  one  ought  to  be  appointed ?    Why? 


270  KEEPING  THE  BODY  IN  HEALTH 

8.  Have  you  ever  heard  of  a  person's  being  immune  to  certain  diseases, 
such  as  whooping  cough  ?    What  does  this  mean  ?    How  is  it  possible  ? 

REVIEW  QUESTIONS 

1.  Mention  some  common  communicable  diseases. 

2.  Would  a  person  who  has  one  of  these  diseases,  but  who  is  not  very 
sick,  be  a  danger  to  other  people,  if  he  should  play  or  study  with  them? 
Why? 

3.  What  does  it  mean  to  be  "in  quarantine"?     Who  in  a  community 
has  authority  to  quarantine  people? 

4.  What  disease  may  one  be  getting  when  his  throat  begins  to  feel 
sore? 

5.  How  does  a  physician  make  a  test  for  diphtheria? 

6.  When  is  a  thing  sterile?    How  can  one  make  a  spoon,  for  instance, 
sterile  ? 

7.  What  is  the  meaning  of  a  culture?    How  does  a  physician  make  a 
culture  of  diphtheria  ? 

8.  What  does  antitoxin  do  in  the  body? 

9.  Has  antitoxin  saved  the  lives  of  many  people  ? 

10.  May  a  person  carry  the  germs  of  diphtheria,  even  if  he  is  not  sick 
himself? 

11.  Why  did  the  health  authorities  put  a  placard  on  the  door  of  Georgia's 
house,  warning  people  not  to  enter  ? 

12.  Why  did  they  forbid  all  the  people  in  the  house  from  going  out  on 
the  street? 

13.  What  did  they  put  on  the  poster  which  they  placed  indoors?    Why 
is  it  necessary  to  give  these  directions  to  a  family  ? 

14.  How  does  a  nurse  disinfect  the  articles  used  by  a  sick  person  ?     Why 
was  it  necessary  to  be  so  careful  about  this  ? 

15.  How  do  people  get  diphtheria  germs? 

16.  Why  are  people  often  careless  about  sending  out  letters  and  other 
things  from  those  who  are  sick  with  contagious  diseases  ? 

17.  At  one  time  did  people  think  children  ought  to  have  all  the  "catch- 
ing" diseases?    Why? 


CHAPTER  XXI 

HEALTH  CRUSADERS 

ALMOST  a  thousand  years  ago  a  great  many  men,  women,  and 
children  of  Europe  undertook  long  and  perilous  journeys  to  the 
Holy  Land,  the  birthplace  of  Christ.  They  went  there  The  Cru- 
with  the  hope  of  rescuing  Jerusalem  from  the  Turks,  saders  of 
who  held  it  and  who  were  hostile  to  the  Christian  oldentimes 
religion.  These  travelers  suffered  hunger  and  pain  without 
complaint  in  order  that  they  might  help  to  spread  the  religion 
of  hope,  good  will,  and  charity  throughout  the  world.  Their 
standard  —  which  served  the  same  purpose  as  a  flag  —  was 
the  cross,  and  the  Latin  word  for  cross  is  Crux,  so  that  all  who 
participated  in  this  undertaking  were  called  "Crusaders";  that 
is,  persons  who  were  loyal  and  devoted  to  the  cause  of  which 
the  cross  was  the  standard  or  emblem.  The  Crusaders  not 
only  wished  to  reestablish  the  Christian  religion  in  the  Holy 
Land,  its  birthplace,  but  they  sought  also  to  teach  the  people 
along  the  route  to  the  Holy  Land  the  rules  of  life  which  their 
religion  upheld.  The  Crusaders  were  bent  upon  doing  good 
to  mankind,  even  at  the  cost  of  great  suffering  and  sacrifice 
to  themselves. 

We  of  to-day  do  not  need  to  engage  in  such  crusades  as 
those  of  long  ago ;  but  there  is  a  need  to  undertake  crusades  of 
other  kinds.  Most  important  of  all,  perhaps,  is  The  Health 
the  Health  Crusade.  We  need  to  fight  disease.  We  Crusade 
need  to  be  devoted  to  the  cause  of  building  our  bodies  so 
that  they  will  be  sound  and  strong,  and  free  from  defects 
of  every  sort.  We  need  to  undertake  such  a  program  of 

271 


L 


days  of  old,  Crusaders  bold 
Rode  forth  to  fight  the  foe, 
And  we  to-day,  as  brave  as  they 
Forth  to  the  battle  go. 
Let's  fight  for  health  and  happiness, 
And  on  each  trusty  blade, 
We'll  write  the  glorious  motto,  HEALTH! 
Hurrah  for  our  Crusade ! 

Courttsv  National  Child  Welfare  Assn.,  Inc. 


HEALTH  CRUSADERS  273 

daily  life  that  we  shall  feel  well  at  all  times  and  prepared  for 
any  tasks  in  which  we  may  need  to  engage.  We  need 
to  live  so  that  we  shall  not  have  to  lose  time  in  sickness  which 
we  wish  to  spend  in  work  or  in  play.  We  need  also  to  join  with 
our  fellows  in  deterring  people  who  do  anything  that  is  danger- 
ous to  the  health  of  the  public.  We  need  to  make  everyone 
understand  that  he  has  no  right  to  do  anything  whatsoever  that 
will  cause  pain  or  disease  to  any  one  else. 

There  is  a  very  great  difference  between  the  Health  Crusade 
and  the  Crusades  that  were  undertaken  by  people  in  early  times. 
I  told  you  that  the  Crusaders  of  olden  days  often  A  Health 
suffered  greatly  from   hunger,   fatigue,   disease,   and  Crusader 
hardship  that  they  might  accomplish  their  purpose ;  ^.s  evefy~ 
but  the  Health  Crusader,  instead  of  suffering  any  gain  and 
sacrifice  or  pain  or  hardship  from  what  he  under-  nothing  to 
takes,  lessens  pain,  disease,  and  hardship.     His  pur-  lose 
pose  is  to  improve  his  own  health  and  that  of  others ;  and  every  thing 
he  does  which  helps  him  to  attain  his  purpose  will  prevent  him 
from  becoming  sick,  will  save  him  from  pains,  will  make  him 
able  to  do  what  he  wishes  to  do  more  successfully  than  he  other- 
wise would  be  able  to  do  it.     The  Health  Crusader  increases 
his  strength,  his  welfare,  his  happiness,  just  in  the  measure  that 
he  is  a  good,  loyal,  and  efficient  Crusader.     To  the  extent  that 
he  overcomes  laziness,  carelessness,  indifference,  ignorance,  and 
appetite,  he  will  be  a  successful  Crusader,  and  a  stronger,  more 
agreeable,  and  happier  person;  so  that  one  has  nothing  to  lose 
and  everything  to  gain  by  engaging  in  a  Health  Crusade. 

Some  years  ago  a  society  was  formed  for  the  purpose  of  com- 
bating tuberculosis  or  consumption.  Every  one  who  becomes  a 
member  of  the  society  pledges  himself  to  do  what  is  necessary 
in  order  to  prevent  the  spread  of  tuberculosis,  and  to  protect 
himself  against  it.  There  had  been  so  many  deaths  from  this 


274  KEEPING  THE  BODY  IN  HEALTH 

dread  disease  that  there  was  danger  that  our  people  would 
be  destroyed  unless  they  could  stamp  it  out.  Fortunately, 
every  one  who  lives  so  as  to  protect  himself  against  tubercu- 
losis loses  nothing  in  any  way,  but  instead  gains  a  great  deal. 
Protecting  one's  self  against  consumption  or  tuberculosis  means 
that  one  lives  in  such  a  way  that  he  is  strong  and  ready  for  any- 
thing any  one  of  his  age  ought  to  be  able  to  do.  This  society 
which  was  fighting  tuberculosis  started,  in  1917,  a  children's 
society,  the  Modern  Health  Crusaders. 

You  must  not  think  of  the  Modern  Health  Crusaders  as  sacri- 


Courtesy  National  Tuberculosis  Assn. 

EVERY  MODERN  HEALTH  CRUSADER  PLEDGES  HIMSELF  TO  OBEY  THE  CRUSADERS'  HEALTH 

RULES. 

ficing  and  suffering  as  the  early  Crusaders  did.  You  must  rather 
think  of  the  Modern  Health  Crusaders  as  simply  taking  advantage 
of  what  is  known  regarding  ways  and  means  of  getting  the  most 
out  of  life.  Every  Modern  Health  Crusader  pledges  himself  to  do 
nothing  that  may  hurt  the  health  of  any  other  person,  to  help 
"Health  keep  home  and  town  clean,  and  to  obey  the  Cru- 
chores  "  saders'  Health  Rules ;  that  is,  to  do  certain  "  health 
chores  "  every  day.  Here  are  indicated  the  chores  for  one  day.1 
(Each  Crusader  has  these  printed  on  a  chart  which  he  carefully 
checks  from  day  to  day.) 

1  Further  details  may  be  obtained  from  the  National  Tuberculosis  Association, 
370  Seventh  Avenue,  New  York  City. 


I  w«hed  n,y  b«b  Be 


-,ffi^£&S*''adl     LSTml 


I  brushed  my 'teeth  thoroughly  after 
bnakiut  and  after  the  evening  nwaL 


air    I  proteaed  others 
coughed  or  sneezed 


I  tried  to  eat  slowly,  and  only  wholesome 
food,  including  milk,  vegetables  and  fruit 


I  tried  hard  to  keep  neat;  to  be  cheerful,  I  played  outdoors  or 

straightforward  and  clean-minded;  and  to  more  than  thirty  min 


with  windows  open 
tes.  I  tried  had  to 
stand  straight 


I  drank  four  glasses  of  water,  drinking 

»m*efore  each  meal,  and  drank  no  tea, 

coffee  nor  any  injurious  drinks. 

Copyright  National  Tu^ercvlosis  Assn. 
HERE  ARE  PICTURES  OF  MODERN  HEALTH  CRUSADERS. 


276 


KEEPING  THE  BODY  IN  HEALTH 


1.  I  washed  my  hands  before  each  meal  to-day. 

2.  I  washed  my  face,  ears,  and  neck,  and  I  cleaned  my  finger  nails. 

3.  I  kept  fingers,  pencils,  and  everything  likely  to  be  unclean  or  injurious 
out  of  my  mouth  and  nose. 

4.  I  brushed  my  teeth  thoroughly  after  breakfast  and  after  the  eve- 
ning meal. 

5.  I  took  ten  or  more  slow,  deep  breaths  of  fresh  air.    I  protected 
others  if  I  spit,  coughed,  or  sneezed. 

6.  I  played  outdoors  or  with  windows  open  more  than  thirty  minutes. 
I  tried  hard  to  sit  and  stand  straight. 

7.  I  was  in  bed  ten  hours  or  more  last  night,  and  kept  my  windows  open. 

8.  I  drank  four  glasses  of  water,  drinking  some  before  each  meal,  and 
drank  no  tea,  coffee,  nor  any  injurious  drinks. 

9.  I  tried  to  eat  slowly,  and  only  wholesome  food  including  milk,  vege- 
tables, fruit.     I  went  to  toilet  at  regular  time. 

10.  I  tried  hard  to  keep  neat ;  to  be  cheerful,  straightforward,  and  clean- 
minded  ;  and  to  be  helpful  to  others. 

11.  I  took  a  full  bath  on  each  day  of  the  week  that  is  checked  (x) . 

In  the  days  of  the  old  Crusades  a  youth  was   given  honors 
gradually,  according  as  he  showed  that  he  had  courage,  endurance, 

loyalty,  devotion,  and  in-  Honors  for 
telligence.  When  he  first  Health 
began  to  prepare  to  be  a  Crusaders 
Knight  he  was  known  as  a  Page. 
After  a  certain  period  when  he  had 
been  well  tested,  if  he  made  a  good 
record  in  regard  to  each  of  the  quali- 
ties required,  he  won  the  title  of 
Squire.  If  he  continued  to  show 
improvement  in  respect  to  all  the 
required  qualities  so  that  he  became 
proficient  in  each  one,  he  was  given  a 
higher  honor ;  that  is,  he  was  made  a  Knight  or,  better  still,  a 
Knight  Banneret.  With  the  modern  Health  Crusaders,  *here  are 


Courtesy  National  Tuberculotit  Assn. 

THIS    IS    A    REPRODUCTION   OF    THE 
PIN  WORN  BY  A  KNIGHT. 


HEALTH  CRUSADERS 


277 


the  same  ranks.  In  order  to  become  a  Squire  one  is  required  to 
do  at  least  fifty-four  health  chores  in  each  of  five  weeks.  During 
the  first  five  weeks  he  is  a  Page.  He  must  do  at  least  fifty-four 
chores  for  ten  weeks  in  order  to  become  a  Knight,  and  he  must  do 
them  for  fifteen  weeks  to  become  a  Knight  Banneret.  A  higher 
title  even  than  Knight  Banneret  may  be  won.  This  will  be 
mentioned  at  another  point  in  the  chapter.  Any  one  who  does 
these  chores  for  fifteen  weeks  will  so  have  formed  the  habit  that 
he  will  probably  continue  to  do  them. 
He  will  have  discovered  then  that 
doing  health  chores  means  simply  liv- 
ing in  ways  that  will  yield  the  greatest 
amount  of  health,  strength,  and  hap- 
piness; and  when  one  finds  this  out 
he  will  not  be  willing  to  drift  back 
into  bad  habits  which  result  in  aches, 
pains,  disease,  and  inefficiency.  In 

the    olden    days    only   boys   became       Courtesv  National  Tuberculosis  Assn. 
knights ;  but  both  boys  and  girls  take   THIS  is  A  REPRODUCTION  OF  THE 

J     .        „ ,         T.  ,       i  -TT        i ,  i      /->  1  PIN  WORN  BY  A  KNIGHT  BANNERET. 

part  in  the  Modern  Health  Crusade. 

Every  boy  or  girl  not  already  a  Modern  Health  Crusader 
should  obtain  a  set  of  health  rules  from  the  National  Tubercu- 
losis Association  and  should  keep  either  at  home  or  at  school  a 
record  of  "  health  chores  "  till  he  or  she  is  a  Knight  Banneret 
and  has  firmly  fixed  the  habits  of  healthful  daily  living. 

If  you  are  a  Boy  Scout  or  a  Camp  Fire  Girl,  you  know  that 
you  must  also  be  a  Health  Crusader.     No  boy  can  Boy  Scouts 
be   a   real   Boy  Scout  who  does  not  try  to  develop  a?d  CamP 
and  keep  a  good,  healthy  body  so  that  he  will  feel  ghoui^be 
well  and  be  ready  for  hikes,  games,  plays,  and  tasks  Health 
that  Boy  Scouts  should  perform.     No  girl  can  be  a  Crusaders 
good  Camp  Fire  Girl  unless  she  can  take  part  in  the  out-of-door 


K 


278 


KEEPING  THE  BODY  IN  HEALTH 


life,  —  swimming,  camping,  hikes  into  the  country  and  into  the 
woods,  —  which  all  Camp  Fire  Girls  should  enjoy.  Do  you  not 
see  that  the  reason  why  we  should  keep  healthy  and  strong  is 
so  that  we  may  do  all  the  things  that  our  companions  can  do 
and  be  a  help  in  the  world,  not  a  hindrance?  This  will  make 


Qodern*  J^ealth*  Cfrusade  ®f» 

Roll  of  • 
foealtri- 
Jfiighthood 


MODERN  HEALTHCRUSADERSl  PUPILS'  WEIGHT  RECORD 

,»»«»  \s>><*'rr^nr[^z^^^«>^^\~\™[~\.~\...\.~\~.\^ 


Courtesy  National  Tuberculosis  Assn. 
THIS    SHOWS    PART    OF    A   SCHOOL   ROLL    OF   HEALTH. 

life  happier  for  ourselves  and  more  agreeable  for  all  those  with 
whom  we  have  any  relations. 

How  can  one  tell  whether  he  is  as  healthy  and  strong  as  he 
should  be?  I  am  going  to  tell  you  how  you  can  determine 
Standards  whether  you  have  as  good  a  body  and  as  fine  health 
as  you  should  have.  By  examining  hundreds  of 
thousands  of  boys  and  girl  of  all  ages,  and  keeping 
a  careful  daily  account  of  their  health,  it  has  been 
possible  to  show  what  a  healthy  body  should  be  at 
different  ages.  You  will  find  it  very  useful  to  com- 
pare your  body  with  the  standard  or  norm;  the  standard  or  norm 
shows  the  kind  of  body  which  thoroughly  sound  and  healthy 
people  of  your  age  should  possess.  In  order  that  you  may  see 
how  you  rank  in  health,  you  should  make  out  a  chart  and  indi- 


or  norms 
in  bodily 
develop- 
ment and 
health 
habits 


HEALTH  CRUSADERS 


279 


cate  how  you  stand  in  regard  to  every  important  point  of 
bodily  development  and  health.  Your  teacher  will  help  you  to 
make  this  chart,  and  when  it  is  made  you  should  show  it  to  her, 
and  then  show  it  to  your  parents  and  keep  it  as  a  record.  You 


RIGHT  HEIGHT  and  WEIGHT 
FOR  BOYS 

Height 
Inches 

5 

Yre. 

6 
Yre. 

7 
Yre. 

8 
Yre. 

9 
Yre. 

10 
Yra. 

11 
Yra. 

12 
Y«. 

13 
Yre. 

14 

Yrs. 

15 

Yre. 

16 
Yre. 

17  |  18 
Yre.  Yw. 

__ 

39 
40 
41 
42 
43 
44 
45 
46 
47 
48 
49 
50 
51 
52 
53 
54 
55 
56 
67 
58 
59 
60 
61 
62 
63 
64 
65 
66 
67 
68 
69 
70 
71 

35 
37 
39 
41 
43 
45 

38 
40 
42 
44 
45 
47 
49 

44 

46 
47 
50 
51 
53 

48 
50 
52 
54 
55 
58 
60 

52 
55 
56 
59 
61 
64 
67 
73 

LI 
59 
62 
65 
68 
71 
74 
77 

62 
65 
68 
71 
75 
79 
81 
84 

68 
72 
70 
70 
82 
85 
88 
90 

76 
80 
83 

87 
89 
92 
97 
100 
104 

84 
88 
91 
94 
99 
102 
106 
112 
118 

$ 

BMkk 
Eta*. 

92 
95 
100 
104 
108 
113 
119 
123 
125 
130 

"Ht^ 

•"•! 

Mi»B 

101 
105 
109 
115 
121 
124 
126 
131 
134 
136 

) 

•!»• 

Mhfc 

•» 

110 
117 
122 
125 
127 
133 
136 
140 
142 

120 
123 
127 
131 
136 
139 
143 
145 

PREPARED  BY  DR.  THOMAS  D.  WOOD 

Courtesy  of  Child  Health  Organization 


should  use  some  such  title  as  this  title  for  your  chart:  "How 
I  Stand  in  Health  Matters." 

First,  you  should  see  how  you  compare  with  the  standard  or 
norm  in  regard  to  weight.     Examine  the  table  for  boys  or  for 


280 


KEEPING  THE  BODY  IN  HEALTH 


girls  to  find  what  you  should  weigh  for  your  height  at  different 
ages.  You  are  not  responsible  for  your  height,  but  you  are 
largely  responsible  for  your  weight;  and  you  can  control  it. 
If  you  weigh  five  pounds  more  or  five  pounds  less  than  the 


RIGHT  HEIGHT  and  WEIGHT 
FOR  GIRLS 

Height 
Inches 

5 

Yre. 

6 
Yre. 

7 
Yre. 

8 
Yre. 

9 
Yre. 

10 
Yre. 

11 
Yre. 

12 
Yre. 

13 

Yre. 

14 
Yre. 

16 
Yre. 

16 
Yre. 

17 
Yre. 

18 
Yre. 

39 
40 
41 
42 
43 
44 
45 
46 
47 
48 
49 
50 
51 
52 
53 
54 
55 
56 
57 
58 
59 
60 
61 
62 
63 
64 
65 

34 
35 
39 
41 
43 
45 

37 
39 
42 
44 
46 
47 
48 

42 
44 
46 
47 
49 
50 
52 

47 
50 
51 
53 
55 
57 

53 
54 
56 
59 
61 
65 

•67 
60 
62 
66 
68 
70 

63 
67 
68 
71 
72 
76 

69 
71 
73 
77 
79 
85 

74 

77 
82 
88 
92 
97 
99 

n.thk  ;•  EJ.MUOB 

H<K.t*B  m  B«altb 

79 
85 
93 
95 
99 
102 
105 
107 

96 

100 
103 
105 
107 
110 
114 

105 
107 
109 
111 
113 
117 
121 

109 
111 
113 
115 
119 
123 

116 
117 
121 
125 

PREPARED  BY  DR.  THOMAS  D.  WOOD 

Courtesy  of  Child  Health  Organization 


norm  for  your  age,  your  record  may  be  considered  excellent 
(use  E  in  marking).  If  you  weigh  seven  pounds  more  or  less 
than  the  norm,  your  record  may  be  considered  good  (use  G  in 
marking).  If  you  weigh  ten  pounds  more  or  less,  your  rec- 


HEALTH  CRUSADERS  281 

ord  is  fair  (use  F  in  marking).  If  you  weigh  fifteen  pounds 
more  or  less,  your  record  is  poor  (use  p  in  marking).  If  you 
weigh  twenty  pounds  more  or  less  than  the  standard,  your 
record  is  very  poor  (use  F  P  in  marking) . 


Courtesy  National  Tuberculosis  Assn. 
THESE  BOYS  AND  GIRLS  ARE  BEING  WEIGHED  BY  THE  SCHOOL  NURSE. 

If  your  record  is  not  excellent  in  respect  to  weight,  you  should 
find   out  what  is   the  matter.     If  you  have  excess  standard 
weight,  you  are  probably  eating  too  much,  perhaps  weight  for 
too  many  sweets.     It  may  be  that  you  eat  between  heisht 
meals  and  so  consume  more  food  than  you  need.     Perhaps  you 


282 


KEEPING  THE  BODY  IN  HEALTH 


do  not  exercise  enough.  If  you  will  study  the  matter,  you  can 
find  out  why  you  are  too  heavy  for  your  height.  If  you  carry 
around  excess  weight,  it  is  a  burden  on  your  heart,  and  you  are 
less  fit  for  any  task  or  game  than  you  should  be. 

If  you  do  not  weigh  enough,  you  should  find  out  whether  you 
are  eating  the  proper  foods,  and  the  right  amount  of  each.  You 
may  be  drinking  tea  or  coffee,  which  make  most  children  very 
nervous  so  that  they  lose  weight  and  feel  badly  in  many  ways. 
You  may  not  have  well-balanced  meals.  You  may  be  getting 
to  bed  too  late  so  that  you  are  not  well-rested.  You  may  not 
have  formed  regular  habits  in  regard  to  getting  rid  of  body  waste. 
This  is  a  very  bad  habit  and  is  the  cause  of  much  ill  health. 

You  can  see  what  well-balanced  meals  are  and  about  what 
amounts  of  each  article  you  should  eat  if  you  will  study  the  fol- 
Regulating  lowing  list  of  sample  meals  for  different  seasons  pre- 

one's  meals  pare(j  by  United  States  government  specialists.     You 

according  .         ,  .  ,  ,. 

to  one's        can  varv  the   amounts   of  each   article   according  as 

weight  you  are  underweight  or  overweight.  If  you  can  se- 
cure good,  wholesome  milk,  you  may  drink  an  additional  glass 
at  each  meal  provided  you  are  not  overweight.  You  may  always 
substitute  eggs  for  meat  if  you  like  them.  You  may  add  lettuce 
and  celery  to  every  dinner  and  supper  whenever  you  can  secure 
them.  Whole  wheat  or  graham  bread  is  better  than  white  bread. 

SAMPLE  SUMMER  DIET  FOR  A  WEEK  FOR  CHILDREN  OF  7  TO  14  YEARS 


BREAKFAST. 

DINNER. 

SUPPER. 

Oatmeal,  ?  to  f  cup,  with  milk. 
Stewed   fruit,    2   to  3   table- 
spoonfuls. 
Bread  and  butter,  2  to  3  slices. 
Milk  to  drink,  i  glass. 

Lamb  stew,  with  vegetables, 
small  portion. 
Squash  or  string  beans,  2  to  3 
tablespoonfuls. 
Bread  and  butter,  2  to  3  slices. 
Bread  pudding,  2  tablespoon- 
fuls. 

Potato  soup,  with  milk,  i 
cup. 
Poached  egg  on  toast. 
Brown  bread  and  butter,  2 
to  3  slices 
Stewed  prunes,  4  to  5. 
Milk  to  drink,  i  glass. 

HEALTH  CRUSADERS 


SAMPLE  SUMMER  DIET  —  Continued. 


BREAKFAST. 

DINNER. 

SUPPER. 

Force  or  corn  flakes,   i  cup, 
with  milk. 
Egg. 
Brown  bread  and  butter,  2  to  3 
slices. 
Milk  to  drink,  i  glass. 

Chicken  with  rice,  small  por- 
tion. 
Mashed  potatoes,  2  to  3  table- 
spoonfuls. 
Dandelion   greens,   or   boiled 
onions,  2  to  3  tablespoon- 
fuls. 
Stewed  fruit,    2   to  3   table- 
spoonfuls. 
Bread  and  butter,  2  to  3  slices. 

Spinach  soup  with  milk,  i  cup. 
Corn  bread  and  sirup,  2  to  3 
pieces. 
Cottage  cheese,  i  level  table- 
spoonful. 
Ginger  cookies,  i. 

Hominy,  ^  to  f  cup,  with  milk. 
Toast  and  butter,  2  to  3  slices. 
Baked  banana,  i. 
Milk  to  drink,  i  glass. 

Bacon,  i  slice. 
Poached  egg  and  spinach. 
Spaghetti  with  tomatoes,  2  to 
3  tablespoonfuls. 
Green  peas  or  string  beans,  2 
to  3  tablespoonfuls. 
Bread  and  butter,  i  to  2  slices. 

Corn  flakes,  i  to  2  cups,  with 
milk. 
Puree  of  lima  beans,  f  cup. 
Ginger  cookies,  i  to  2. 
Milk  to  drink,  i  glass. 

Corn  meal,   \  to  f  cup,  with 
sirup. 
Scrambled  egg,  i. 
Bread  and  butter,  2  to  3  slices. 
Milk  to  drink,  i  glass. 

Rice  pudding,   i  to   2   table- 
spoonfuls. 
Hamburg  steak,  i  small  ball. 
Stewed  potatoes,  2  to  3  table- 
spoonfuls. 
New     beets     and     beet-top 
greens,  2  to  3  tablespoonfuls. 
Stewed   fruit,    2   to   3    table- 
spoonfuls. 
Bread  and  butter,  2  to  3  slices. 

Milk  toast  or  rice,  \  cup,  with 
milk. 
Baked  potato,  i. 
Bread  and  butter,  2  to  3  slices. 
Milk  to  drink,  i  glass. 

Shredded  wheat,  i,  with  milk. 
Corn  bread  and  butter,  2  pieces. 
Apple  sauce  or  stewed  pear,  2 
to  3  tablespoonfuls. 
Milk  to  drink,  i  glass. 

Fish  or  clam  chowder,  f  cup, 
or  egg. 
New  beets  or  spinach,  2  to  3 
tablespoonfuls. 
Boiled  potato. 
Bread  and  butter,  2  to  3  slices. 
Custard  or  junket,  £  cup. 

Oatmeal  soup,  i  cup. 
Squash,   chard,  or    carrots,  2 
to  3  tablespoonfuls. 
Stewed   fruit,   2    to  4  table- 
spoonfuls. 
Bread  and  butter,  2  slices. 
Milk  to  drink,  i  glass. 
Plain  cookies,  i. 

Force  or  corn  flakes,   i  to  2 
cups,  with  milk. 
Poached  egg  on  toast. 
Brown  bread  and  butter,  2  to  3 
slices. 
Milk  to  drink,  i  glass. 

Lamb    hash    or   veal    cutlet, 
small  portion. 
String  beans,  2  tablespoonfuls. 
Baked  potato. 
Bread    and   butter,    2    to    3 
slices. 
Apple   sauce,    2   to   4   table- 
spoonfuls. 

Rice  and  milk,  f  cup. 
Corn  bread  and  butter,  2  slices. 
Ginger  cookies,  i  to  2. 
Milk  to  drink,  i  glass. 

284 


KEEPING  THE  BODY  IN  HEALTH 

SAMPLE  SUMMER  DIET  —  Continued. 


BREAKFAST. 

DINNER. 

SUPPER. 

Rice,  |  cup,  with  milk. 
Bread  and  butter,  2  to  3  slices. 
Stewed   fruit,    2    to   3    table- 
spoonfuls. 
Milk  to  drink,  i  glass 

Dried  pea  or  bean  soup,  i  cup. 
Baked  potato. 
Bread  and  butter,  2  to  3  slices. 
Lima  beans  or  new  beets,   2 
tablespoonfuls. 
Ice  cream  or  fruit  sherbet,  2 
tablespoonfuls. 

Baked  potato,  i. 
Poached  egg  on  toast,  i. 
Stewed  prunes,  4  to  5. 
Plain  cookies,  i  to  2. 
Milk,  i  glass. 

For  the  younger  children  use  more  milk  and  less  meat. 


SAMPLE  WINTER  DIET  FOR  A  WEEK  FOR  CHILDREN  OF  7  TO  14  YEARS. 


BREAKFAST. 

DINNER. 

SUPPER. 

Oatmeal,  f  cup,  with  milk. 
Bread  and  butter,  2  to  3  slices. 
Baked  apple,  i. 
Milk  to  drink,  i  glass. 

Roast     lamb,     small     slice; 
baked  potatoes. 
Beets,  onions,  or  oyster  plant, 
2  to  3  tablespoonfuls. 
Rice  pudding,   2  to  3  table- 
spoonfuls. 
Bread  and  butter,  2  to  3  slices. 

Scrambled  egg,  i. 
Bread  and  butter,  2  to  3  slices. 
Oatmeal  cookies,  i  to  2. 
Milk  to  drink,  i  glass. 

Hominy,  f  cup,  with  milk. 
Bread  and  butter,  2  to  3  slices. 
Bacon,  i  slice. 
Cocoa  with  milk,  i  cup. 

Vegetable  soup,  with  carrots, 
beans,  onions,  i  cup. 
Spinach   with   poached   egg,1 
2  to  3  tablespoonfuls. 
Corn  bread  and  butter,  2  to  3 
slices. 
Dates,  4  to  5. 

Baked  potato,  i. 
Bread  and  butter,  2  to  3  slices. 
Stewed  apricots,  2  to  3  table- 
spoonfuls. 
Cottage  cheese,1  1  tablespoon- 
ful. 

Corn  meal,  \  to  §  cup,  with 
milk. 
Toast  and  butter,  2  to  3  slices. 
Apple  sauce,  2  to  4  tablespoon- 
fuls. 
Milk  to  drink,  i  glass. 

Rice  and  meat  loaf,  small  por- 
tion. 
Stewed  celery  and  cauliflower, 
2  to  3  tablespoonfuls. 
Bread  and  butter,  2  to  3  slices. 
Baked     Indian     pudding,     2 
tablespoonfuls. 

Rice  and  milk,  |  cup. 
Baked  banana,  i. 
Fruit  cookies,  i  to  2. 
Bread  and  butter,  3  to  4  slices. 

1  Toward  spring,  when  eggs  are  abundant,  they  may  be  given  more  frequently,  replacing 
some  meat  and  milk.  Cottage  cheese  should  be  made  at  home  or  the  best  grade  purchased 
and  used  only  when  fresh. 


HEALTH  CRUSADERS 


SAMPLE  WINTER  DIET  —  Continued. 


BREAKFAST. 

DINNER. 

SUPPER. 

Oatmeal,  |  cup,  with  milk. 
Bread  and  butter,  2  to  3  slices. 
Stewed  prunes  or  figs,  3  to  4. 
Cocoa  with  milk,  i  glass. 

Beef    stew    with    vegetables, 
small  portion. 
Bread  and  butter,  3  to  4  slices. 
Rice  pudding  or  custard,  2  to  3 
tablespoonfuls. 

Corn  bread  and  sirup,  2  to  3 
pieces. 
Soft  egg. 
Bread,  2  to  3  slices,  and  pea- 
nut butter,  5  tablespoonful. 
Cocoa  with  milk,  i  glass. 

Force  or  corn  flakes,   i  to  2 
cups,  and  milk. 
Bread  and  butter,  2  to  3  slices. 
Soft  egg  and  bacon,  i. 
Milk  to  drink,  i  glass. 

Chicken,  small  slice;    potato 
soup  with  milk,  2  to  3  cups. 
Creamed  carrots  or  onions,  2 
to  3  tablespoonfuls. 
Gingerbread  and  thin  cream, 
i  small  piece. 
Bread  and  butter,  2  to  3  slices. 

Milk  toast,  2  to  3  slices. 
Cottage  cheese,  i  tablespoon- 
ful. 
Stewed  prunes,  4  to  5. 
Cookies;     milk    to    drink,   i 
glass. 

Pettijohn   or   malt   breakfast 
food,  f  cup,  with  milk. 
Bread  and  butter,  2  to  3  slices. 
Soft  egg;    milk  to  drink,    i 
glass. 

Creamed  or  fresh  broiled  fish, 
small  portion. 
Baked  apple,  i. 
Bread    and    butter,    2    to    3 
slices. 

Spinach  or  bean  soup,  i  cup. 
Baked  potato,  i. 
Corn    bread    and   butter,   2 
pieces. 
Milk  to  drink,  i  glass. 

Corn  meal,  -|  cup,  and  milk. 
Toast  and  butter,  2  to  3  slices. 
Stewed  dried  peaches,  2  to  3 
tablespoonfuls. 
Cocoa  with  milk,  i  cup. 

Lamb  stew,  with  vegetables, 
small  portion. 
Baked  sweet  potato,  i. 
Boiled  potato,  i. 
Bread  or  rice  pudding,  2  to  3 
tablespoonfuls. 
Bread  and  butter,  2  to  3  slices. 

Celery  soup  with  milk,  i  cup. 
Bread  and  butter,  2  to  3  slices. 
Custard  or  junket,  £  cup. 
Ginger  cookies,  i  to  2  ;  milk 
to  drink,  i  glass. 

You  have  been  learning  how  to  make  your  weight  conform  to 
the  standard  for  your  age.     You  need  to  compare  yourself  with 
the  standard  or  norm  in  respect  to  other  matters  scoring 
also.     You   must   have   your    eyes    examined.     You  one's  eye- 
should  be  able  to  see  letters  of  a  certain  height  and  sight 
thickness  clearly  at  a  given  distance.     An  oculist  should  make  the 
examination.     He  will  tell  you  whether  you  have  excellent,  good, 
fair,  or  poor  eyes.     If  you  have  anything  but  excellent  eyes 
and  do  not  wear  glasses    that   correct   the   defect,  you  must 
score  yourself  on  your  chart  to  show  that  you  are  not  up  to 
standard. 


286  KEEPING  THE  BODY  IN  HEALTH 

You  should  be  able  to  hear,  with  each  ear,  the  ticking  of  an 
ordinary  watch  at  a  distance  of  five  or  six  feet.  If  you  have  to 
Scoring  bring  it  as  close  as  three  feet,  you  have  poor  hearing, 
one's  hear-  Your  physician  can  perhaps  discover  the  cause  for 
ing  and  this  and  remove  it.  You  should  score  yourself  also 
mg  in  regard  to  breathing.  If  the  nasal  passages  are 
not  free  and  clear  so  that  you  can  breathe  through  them  at  all 
times,  even  when  you  are  running  hard,  your  breathing  is  not 


UNLESS  THESE  BOYS  RECEIVE  ATTENTION  FROM  A  CAPABLE  DENTIST  THEY  WILL  BE  SERI- 
OUSLY HANDICAPPED  IN  THE  RACE  OF  LIFE.  HEALTH  IS  INJURED  AND  THE  APPEARANCE 
MARRED  BY  DECAYING  OR  ILL-FORMED  TEETH. 

excellent.  If  you  breathe  through  the  mouth  frequently,  you 
should  score  your  breathing  as  poor.  You  should  have  a  physi- 
cian examine  you  to  see  if  you  have  adenoids  or  enlarged  ton- 
sils. If  you  have  either,  you  must  score  your  breathing  as  poor , 


HEALTH  CRUSADERS  •   287 

because  they  will  interfere  with  it.  If  you  have  both,  your  score 
is  very  poor.  A  surgeon  could  very  quickly  and  easily  make 
you  good  or  excellent  in  respect  to  these  matters. 

You  must  score  yourself  in  regard  to  teeth.     If  your  teeth 
are  all  sound  and  clean,  you  should  score  yourself  excellent  in  that 
respect.     If  you  have  several  teeth  that  are  decaying,  scoring  in 
score  your  teeth  poor.     If  you  have  any  aching  teeth  regard  to 
that  have  not  been  treated  by  a  dentist,  you  must  score  teeth 
very  poor.    You  can  very  easily  change  your  record  from  very 
poor  to  excellent  if  you  will  visit  a  good  dentist.     If  your  teeth 
are  dirty,  you  must  not   score  yourself  higher  than  fair  until 
they  are  clean. 

Next,  you  should  see  if  you  have  any  enlarged  glands.     You 
have  learned  that  the  proper  working  of  these  glands  is  very 
important  for  good  health.     If  you  have  one  enlarged  Enlarged 
gland,  your  score  is  poor;  if  more,  very  poor.  glands 

Your  spinal  column  should  be  examined  by  your  physical  cul- 
ture teacher  or  a  physician,  and  if  you  have  any  spinal  curva- 
ture your  score  is  very  poor.     You  can  have  this  cor-  spinal 
rected  readily  if  you  do  not  wait  until  it  is  too  late,     curvature 

You   must   score   your    chest   development.     Your   physical 
training  teacher  will  measure  different  parts  of  your  chest  and 
tell  you  whether  your  development  is  excellent,  good,  Q^est  $e_ 
fair,  or  poor.     If  it  is  found  to  be  poor,  you  can  easily  velopment 
change  your  score  to  good  or  excellent  by  exercises  and  expan- 
which  will  develop  the  chest.     Deep  breathing  ex-  s 
ercises  will  increase  your  expansion.    A  good  chest  expansion 
is  very  important. 

You  know  that  sound  lungs  are  absolutely  necessary  for  good 
health.      A    physician   can    tell    you    very    quickly  Sound 
whether  any  part  of  either  of  your  lungs  is  undevel-  lunss 
oped  or  diseased.    If  you  do  not  score  excellent  in  regard  to  lungs, 


288 


KEEPING  THE  BODY  IN  HEALTH 


you  can  probably  discover  why  you  are  deficient,  and  so  change 
your  habits  that  you  will  be  able  to  improve  your  score. 

You  should  have  the  arch  of  the  foot  examined.  Some 
The  arch  people  have  what  is  known  as  " broken  arch." 
of  the  foot  This  is  bad  for  the  health.  It  can  be  corrected 
if  taken  in  time. 

Here  is  the  chart,  then,  for  scoring  yourself  in  regard  to  a 
healthy  body. 


1ST 

Mo. 

2ND 

Mo. 

3RD 

Mo. 

4TH 

Mo. 

5TH 

Mo. 

6TH 

Mo. 

7TH 

Mo. 

STH 
Mo. 

QTH 

Mo. 

i.   Weight      .... 

2.   Eyes     

3.   Ears     

4.   Breathing 

5.   Teeth  .          ... 

6.    Glands      .... 

7     Spinal  column  . 

8    Chest  development 

9    Lungs 

10    Arch  of  foot 

In  the  Modern  Crusade  Movement,  there  is  an  honor  higher 
than  becoming  Knight  Banneret.  It  is  to  be  a  Knight  of  the 
Round  Table.  Crusaders  earn  points  toward  winning  a  seat 
at  the  round  table  through  such  tests  for  physical  fitness  as 
you  have  just  read  about,  —  tests  for  good  weight,  good  eye- 
sight, hearing,  posture,  and  the  other  qualifications.  What 
a  fine  country  we  should  have  if  all  the  boys  and  girls  in  it  were 
fit  to  be  Knights  of  the  Round  Table ! 


APPENDIX 


TABLES  OF  COMPOSITION  OF  FOODS 

You  should  keep  the  following  tables  for  reference,  so  that 
you  can  tell  what  nutrients  are  to  be  found  in  all  the  ordinary 
foods.  The  meaning  of  the  figures  in  these  tables  is  clear  when 
you  remember  that  for  every  100  pounds  of  milk,  87.0  pounds 
are  water,  3.3  pounds  are  protein,  etc. 

PROTEIN  FOODS  —  COMPOSITION 


FOOD 

WATER 

PROTEIN 

FAT 

CARBOHY- 
DRATES 

ASH 
MINERAL 

Milk     

Errors 

87.0 
73  7 

3-3 
14  8 

4.0 
IO  ^ 

5-o 

0.7 
I  O 

Cheese 

-7  A   O 

24  3 

-2  -7     A 

4t 

-i  8 

Fowl     
Beef      

63.7 

61  o 

19-3 

18  6 

I6.3 

18  q 

o 

I.O 
I  O 

Fish  (lean)     .     .     . 

82.5 

15.8 

0.4 

1.2 

U.  S.  Department  of  Agriculture. 
GENERAL  COMPOSITION  OF  GRAINS 


GRAINS 

WATER 

PROTEIN 

FAT 

CARBO- 
HY- 
DRATES 

CELLU- 
LOSE 

ASH 
MINERAL 

Bread,  Graham  (whole  meal) 
Macaroni  . 

35-7 

T  -7     T 

8.9 
O  O 

1.8 

O  T. 

52.1 
76  8 

I.I 

i-5 

o  8 

Wheat  . 

II    A. 

i?  8 

W-O 

I  O 

7  1  O 

O  O 

I  O 

Oats  (meal)   .     . 

J.J..4 

7  -7 

J.^.0 

16  i 

A.y 

72 

67  q 

o  o 

I.O 

Barley  .     . 

II    £ 

8  c 

I  I 

77  8 

O  3 

i  i 

Corn  (green)  

AJ"3 

7?  A 

°o 

o  i 

I  i 

IQ.7 

o.< 

0.7 

Rice      

O  3 

80 

O  3 

70.  0 

O.2 

0.4 

289 


2  go 


APPENDIX 


GENERAL  COMPOSITION  OF  FRUITS 


EDIBLE  PORTION  FRUIT 

WATER 

PROTEIN 

FAT 

CARBOHY- 
DRATES 

CELLU- 
LOSE 

ASH 
MINERAL 

Gooseberries  .... 

85-6 

I.O 

I3-I 

0-3 

Currants    

8^  o 

i.e 

12.8 

O  7 

Whortleberries    .     .     . 

82.4 

**o 

0.7 

3.0 

3-2 

v->.  / 

0.4 

Blueberries  \      .     .     . 

Cranberries  /       ... 

88.9 

0.4 

0.6 

9-9 

i-5 

0.2 

Grapes 

77  4. 

1.3 

1.6 

19.2 

42 

Ot 

Blackberries  .... 

/  /  'T- 

I.O 

10.9 

•o 

2.5 

•  ^ 
0-5 

Raspberries  (blk.)    .     . 

84.1 

1-7 

I.O 

12.6 

0.6 

Strawberries  .... 

90.4 

I.O 

0.6 

74 

1.4 

0.6 

Melons  

89.5 

0.6 

9-3 

2.1 

0.6 

Watermelons  .... 

92.4 

0.4 

0.2 

6.7 

o-3 

Pineapples      .... 

89.3 

0.4 

0-3 

9-7 

0.4 

o-3 

Bananas     

Hf      .3 

1.7 

0.6 

22.O 

I.O 

0.8 

Apples            .... 

846 

O 
O.4 

O-5 

14.2 

1.2 

O  1 

Pears 

Wij..  \J 

8d  4. 

0.6 

0.5 

I4.I 

2  7 

o 
O.4 

Peaches      .     .     .  '  . 

*J'f  "T- 

80.4. 

0.7 

O.I 

0  4. 

**  I 

?  6 

O  4. 

Plums 

uy.if. 

78  4 

/ 

I.O 

V'T" 
2O.  I 

O  * 

W«£f 
O.^ 

Cherries     

/  "•f 
80.9 

I.O 

0.8 

I6.7 

O.2 

0.6 

Oranges     

86  9 

0.8 

O.2 

n.6 

0.5 

Dates  (dried)      .     .     . 

*Jvy  •  V 

i54 

2.1 

2.8 

784 

Figs  (dried)    .... 

18.8 

4-3 

0.3 

74.2 

2.4 

Prunes  (dried)     .     .     . 

22.3 

2.1 

73-3 

2.4 

Raisins  (dried)    .     .     . 

14.6 

.     2.6 

3-3 

76.1 

34 

Olives    

67.0 

2-5 

9.0 

44 

THE  COMPOSITION  OF  LEGUMES 


LEGUMES 

WATER 

PROTEIN 

FAT 

CARBOHY- 
DRATES 

CELLU- 
LOSE 

ASH 
MINERAL 

Lima  beans  (dried) 

10.4 

18.1 

i-5 

65-9 

4.1 

String  beans  .... 

89.2 

2-3 

•3 

74 

1.9 

.8 

Green  peas     .... 

74.6 

7.0 

•5 

16.9 

i-7 

I.O 

Peas  (dried)    .... 

9-5 

24.6 

I.O 

62.0 

4.5 

2.9 

Lentils  (dried)     .     .     . 

8.4 

25-7 

I.O 

59-2 

5-7 

Beans  (dried)      .     .     . 

12.6 

22.5 

1.8 

59-6 

44 

3-5 

APPENDIX 


291 


GENERAL  COMPOSITION  OF  NUTS 


EDIBLE  PORTION  NUTS 

WATER 

PROTEIN 

FAT 

CARBOHY- 
DRATES 

CELLU- 
LOSE 

ASH 
MINERAL 

Coconuts 

14  I 

c.7 

c;o.  6 

27  Q 

17 

Almonds 

48 

21  o 

t/t    Q 

17  3 

2  o 

2  O 

Pecans       

2.7 

9-6 

70.5 

15-3 

1.9 

Hickory  nuts       .     .     . 

3-7 

15-4 

67.4 

II.4 

2.1 

Filberts 

7  7 

i<?  6 

6c  7 

13  O 

2  4. 

Brazil  nuts     .... 

5-3 

17.0 

66.8 

7.0 

3-9 

Chestnuts       .... 

AX  O 

6  2 

IT    A 

4.2  I 

i  8 

i  3 

Walnuts  (black)       .     . 

2-5 

27.6 

56,3 

II.7 

i-7 

1.9 

Peanuts      

9.2 

25-8 

38.6 

24.4 

2-5 

2.0 

GENERAL  COMPOSITION  OF  VEGETABLES 


EDIBLE  PORTION  VEGETABLES 

WATER 

PROTEIN 

FAT 

CARBOHY- 
DRATES 

CELLU- 
LOSE 

ASH 
MINERAL 

Potatoes     

78  * 

"7    2 

O  I 

18.4 

O.4 

I  O 

Sweet  potatoes    .     .     . 
Carrots      
Turnips      

69.0 

88.2 
89  6 

.8 
.1 

7 

0.7 
0.4 
O  2 

27.4 

9-3 
8  i 

i-3 

i.i 

i  T. 

I.I 
1.0 

08 

Radishes 

91  8 

•1 

O  I 

t  8 

O  7 

I  O 

Beets     

87.? 

.6 

O.I 

0-7 

O.Q 

I.I 

Parsnips    

ST.  o 

6 

O  < 

J7     t 

2   C 

I  4 

Cabbage 

QI   ^ 

6 

O  1 

q  6 

I   I 

I  O 

Cauliflower     .... 
Spinach 

92.3 
02  3 

1.8 

2  I 

o-5 
o  i 

4-7 

7.2 

I.I 

o.o 

0.7 
2.1 

Celery  

04..  c 

I.I 

O.I 

7.7 

O.I 

Asparagus      .... 

04  O 

i  8 

O.2 

7.7 

0.8 

O.7 

Cucumber 

Q^  4 

o  8 

O  2 

7     I 

O.7 

QC 

Tomatoes  

Q4..  7 

O.Q 

0.4 

7.9 

0.6 

O.< 

Squash 

88  * 

I  4. 

OX 

o.o 

0.8 

0.8 

Onions 

87  6 

i  6 

O  "? 

Q.Q 

0.8 

0.6 

APPENDIX 

GENERAL  COMPOSITION  OF  FATS 


FATS 

WATER 

PROTEID 

FAT 

CARBO- 
HYDRATES 

ASH 
MINERAL 

Butter  
Olive  Oil    .... 
Cream       .... 

II.  0 

74  O 

I.O 

85.0 
100.0 

18  ? 

4r 

3-0 

o  ^ 

AVERAGE  COMPOSITION  OF  FOODS 


FRUIT 

NUTS 

LEGUMES 

Water         

8<-QO% 

4-c% 

10—14  2O% 

Proteid 

e% 

I  ^  —  2O% 

I  ^  81—  2^  16% 

Fat    

.0=:% 

^0-60% 

0  c;8-2.4.6% 

Carbohydrates     
Cellulose 

5i-io|% 

2\% 

9-12% 

T.-^r 

52-12% 

2-3% 

Mineral  matter    .     .     . 

•05% 

1% 

GLOSSARY 
KEY  TO   PRONUNCIATION 

a,  as  in  ale;  a,  as  in  sen'ate;  a,  as  in  care;  a,  as  in  am;  a,  as  in  arm; 
a,  as  in  ask ;  a,  as  in  all ;  a,  as  in  fi'nal ;  e,  as  in  eve ;  e,  as  in  e-vent' ; 
e,  as  in  end;  e,  as  in  fern;  e,  as  in  re'cent;  I,  as  in  ice;  i,  as  in  i-de'a; 
i,  as  in  ill;  6,  as  in  old;  o,  as  in  o-bey';  6,  as  in  orb;  6,  as  in  odd;  u, 
as  in  use;  u,  as  in  u-nite';  u,  as  in  up;  u,  as  in  urn;  y,  as  in  pit'y; 
ob,  as  in  food;  oo,  as  in  foot;  ou,  as  in  out;  oi,  as  in  oil. 

A 

abdominal  cavity  (ab-dom'i-nal  kav'i-ty).  The  hollow  place  in  the  body 
in  which  the  organs  of  the  abdomen  are  situated. 

abscess  (ab'ses).  A  collection  of  pus  in  any  tissue  or  organ  of  the  body, 
due  to  infection. 

abstinence  (ab'sti-n^ns).  The  act,  or  practice,  of  denying  oneself,  par- 
ticularly as  applied  to  drinking  alcoholic  beverages  and  to  smoking. 

acetanilid  (as'et-an'i-lid  or  -lid).  A  medicinal  compound  of  aniline  with 
acetyl,  used  to  relieve  fever  or  pain,  but  dangerous  when  used  with- 
out a  physician's  order. 

adenoids  (ad'e-noids).  Growths  that  form  in  the  nasal  passages  and 
interfere  with  breathing. 

albumen  (al-bu'men).  One  ebrr>ent  of  food,  found  in  the  white  of  an 
egg  and  elsewhere. 

alimentary  canal  (aTi-men'fi-ry  ka-naT).  The  whole  length  of  the  food 
channel  extending  through  the  body. 

alkalinity  (al'ka-lm'i-ty).  Having  the  quality  of  an  alkaline  substance; 
that  is,  a  substance  like  soda,  opposed  to  acidity. 

amoeba  (a-me'ba).     A  tiny  animal  that  consists  of  just  one  cell. 

anaemia  (a-ne'mi-a).  An  unhealthy  condition  of  the  blood,  in  which  there 
is  too  little  blood  in  the  body  or  in  which  the  blood  itself  is  lacking 
in  some  essential  quality. 

293 


294  GLOSSARY 

analogous  (a-naTo-gus).     Having  a  likeness  to  something  else. 

anterior  chamber   (an-te'ri-er  cham'ber).     The  inclosed  space  in  the  eye 

in  front  of  the  lens, 
antiseptic  (an'ti-sep'tic).     Anything,  usually  a  liquid,  that  prevents  decay 

or  that  protects  one  from  germs. 
anvil  (an'vil).     One  of  the  three  small  bones  in  the  ear.     This  bone  has  a 

shape  like  that  of  a  blacksmith's  anvil. 
aorta  (a-or'ta).     The  great  artery  which  carries  the  blood  from  the  heart 

to  all  parts  of  the  body  except  to  the  lungs ;    the  main  trunk  of  the 

arterial  system. 

apex  (a'peks).     The  tip,  point,  of  anything;   as  the  apex  of  the  heart, 
apoplexy    (ap'o-pleks'y).     The    pressure   of  blood    in   the   brain,    which 

causes  a  blood  vessel  to  burst, 
aqueous  humor  (a'kwe-us  hu'mer).     A  fluid  in  the  eye  which    fills   the 

anterior  chamber. 

arterioles  (ar-te'ri-6lz).     Very  small  arteries, 
arterio-sclerosis    (ar-te'ri-6-skle-ro'sis).     The   hardening  of   the   arteries, 

due  usually  to  bad  habits  of  living  in  respect  to  eating,  drinking,  and 

smoking, 
assimilation    (as-sim'i-la'shun).     The    process    of    changing    blood    into 

tissues  and  organs. 
auditory  canal  (a'di-to-ry  ka-naT).     The  tube  from  the  opening  of  the 

ear  to  the  drum  of  the  ear. 
auricle  (a'ri-k'l).     One  of  the  compartments   in   the   heart  that  receives 

the  blood  from  the  veins.     Its  name  comes  from  its  likeness  to  the 

outside  ear. 

B 
bacillus  (ba-sil'us).     A  tiny  vegetable  organism  often  the  cause  of  disease; 

a  variety  of  bacterium, 
bacteria  (bak-te'ri-a).     The  plural  of  bacterium.     Tiny  plants  that  grow 

in  the  body.     Some  are  harmful ;   some  helpful. 
bicuspids  (bi-kus'pids).     The  two  double-pointed  teeth  which  grow,  one 

on  each  side  of  the  jaw,  between  the  cuspids  and  the  molars. 
bile  (bil).     A  yellow  or  greenish  fluid  found  in  the  liver, 
biliousness  (bil'yus-nes).     The  state  of  the  body  when  there  is  too  much 

bile  in  the  system, 
bismuth  (biz'muth).      A  substance  sometimes  administered  to  indicate, 

under  the  X-ray,  the  course  which  food  takes  in  the  alimentary  canal. 


GLOSSARY  295 

bronchi  (bron'ki).     The  plural  of  bronchus.     The  tubes  that  carry  the 

air  from  the  windpipe  into  the  lungs. 
bronchioles  (bron'ki-oles).     Tiny  bronchial  tubes. 

C 

caffeine  (kaf-fen').     A  white,  bitter  substance  found  in  coffee ;   a  poison. 

calorie  (kaTo-ri).  A  unit  of  heat.  Just  as  in  measuring  a  straight  line, 
we  begin  with  the  inch,  so  in  measuring  heat,  we  begin  with  the  cal- 
orie. 

capillary  (kap'il-la-ry  or  ka-pil'la-ry).  A  tiny  thin-walled  tube;  partic- 
ularly one  of  the  smallest  blood  vessels  connecting  arteries  and 
veins. 

carbohydrates  (kar'bo-hi'drats).  Food  elements,  including  principally 
sugars  and  starches. 

carbonic  acid  gas  (kar-bon'ik  as'id  gas).  The  substance  which  a  plant 
takes  from  the  air  and  which  is  thrown  off  from  the  lungs  of  animals 
in  breathing. 

cardiac  (kar'di-ak).     Pertaining  to  the  heart. 

cartilage  (kar'ti-laj).  An  elastic  tissue  found  mainly  in  the  body  between 
joints  and  at  the  ends  of  bones. 

cell  (sel).  One  of  the  tiny  structures  that  compose  the  greater  part  of 
the  tissues  and  organs  of  the  body. 

cellulose  (sel'u-lds').  The  delicate  framework  that  remains  when  the 
soluble  part  of  starch  is  removed  by  saliva  or  pepsin. 

centenarian  (sen'te-na'ri-<2n).     A  person  one  hundred  years  old  or  more. 

centigrade  (sen'ti-grad).  Consisting  of  one  hundred  degrees;  used  to 
describe  a  thermometer  on  which  the  freezing  point  of  water  is  o° 
and  the  boiling  point  is  100°. 

cerebellum  (ser'e-bel'lum).  The  little  brain.  It  controls  the  action  of 
the  muscles. 

cerebrum  (ser'e-brum).  The  larger  division  of  the  brain.  It  is  con- 
cerned in  reasoning  and  willing. 

choroid  (ko'roid).     The  middle  coat  of  the  eyeball. 

chronic  (kron'ik).     Continuing  for  a  long  time;   lingering;   habitual. 

chyme  (kim).  The  name  given  to  food  we  have  eaten  when  it  is  a  half- 
digested,  pulpy  mass.  The  food  is  in  this  state  in  the  small  intestine. 

cilia  (sil'i-a).  The  plural  of  cilium,  which  is  rarely  used.  Tiny  hairs  in 
the  air  passages,  especially  the  nostrils. 


2Q6  GLOSSARY 

circular  muscles  (ser'ku-lar  mus"les).     The  muscles  that  go  around  an 

organ  or  an  opening. 

clot  (klot).     A  thickened,  congealed  mass;   as,  a  clot  of  blood, 
cocaine  (ko'ka-in).     A  substance  used  to  deaden  pain;   a  poison, 
cochlea  (kok'le-a).     The  part  of  the  ear  at  the  entrance  of  the  inner 

ear. 

colic  (kol'ik).  A  severe  pain  in  the  abdomen, 
colon  (ko'lon).  A  part  of  the  large  intestine, 
coma  (ko'ma).  A  state  of  unconsciousness  from  which  it  is  difficult  or 

impossible  to  arouse  a  person. 

combustion  (kom-bus'chun).     The  process  of  burning, 
contaminated     (kon-tam'i-na'ted).     Made     foul;      polluted;      stained; 

soiled ;  dangerous ;  as  when  milk  or  water  is  contaminated  by  germs 

of  typhoid  or  other  diseases, 
convolutions   (kon'vo-lu'shunz).     Irregular  winding  folds  of  an  organ; 

as,  the  convolutions  of  the  brain ;   the  convolutions  of  the  intestines, 
cornea  (kor'ne-a).     The  part  of  the  coat  of  the  eyeball  which  covers  the 

iris  and  the  pupil  and  lets  in  light  to  the  inside  of  the  eye. 
corpulence  (kor'pu-kns).  Excessive  amount  of  fat ;  fleshiness. 
cortex  (kor'teks).  The  outer  part  of  an  organ ;  as  the  cortex  of  the  brain, 

which  is  composed  of  the  outer  layers  of  nerve  cells, 
cranium  (kra'ni-um).     The  skull;   the  bony  case  for  the  brain, 
crystalline  lens  (kris'tal-lin  or  -lin  lenz).     The  part  of  the  eye  that  brings 

the  rays  of  light  to  a  point, 
cuspids  (kus'pidz).     The  teeth  that  have  but  one  point  (or  cusp)  on  the 

crown. 


dermis  (der'mis).     The  layer  of  skin  beneath  the  scarfskin  or  epidermis, 
diaphragm  (di'a-fram).     The  muscle  that  separates  the  cavity  of  the 

chest  from  that  of  the  abdomen, 
dietary  (di'et-a-ry).     Pertaining  to  diet;  that  is,  to  the  amount  and  kind 

of  food  one  eats, 
digestion  (di-jes'chun).     The  changing  of  foods  into  such  form  that  the 

blood  can  absorb  the  useful  parts  and  the  body  throw  off  the  useless 

parts. 

dilate  (di-lat'  or  di-lat').     To  enlarge;  to  swell;  to  expand, 
duct  (dukt).     A  tube  or  canal. 


GLOSSARY  297 

£ 

emulsified  (e-mul 'si-fid).     Subdivided  into  tiny  particles  of  fat;   reduced 

from  an  oily  substance  to  a  milky  fluid,  as  when  olive  oil  is  blended 

with  lemon  juice.- 

endurance  (en-dur'ans).     The  quality  of  being  able  to  keep  up  an  exer- 
tion, or  to  bear  pain,  for  a  considerable  length  of  time, 
enzyme    (en'zlm).     A   substance   made   by   the   salivary   glands,   which 

causes  fermentation  and  is  necessary  for  the  digestion  of  starch, 
epidermis  (ep'i-der'mis).  The  outer  layer  of  the  skin;  the  scarfskin. 
epiglottis  (ep-i-glot'tis).  The  lid-like  covering  which  closes  the  glottis 

while  food  or  drink  passes  through  the  pharynx. 
epithelial  cells  (ep'i-the'li-al  selz).     Cells  that  cover  the  surface  of  the 

body  and  line  all  the  cavities  of  the  body. 

epithelium  (ep-i-the'li-um).     The  covering  formed  by  the  epithelial  cells. 
esophagus   (e-sof'a-gus).     The  part  of  the  alimentary  canal  between  the 

pharynx  and  the  stomach ;   the  gullet. 
eustachian  tube  (u-sta'ki-an  tub).     The  tube  that  leads  from  the  eardrum 

to  the  pharynx. 

excrete  (eks-kret').     To  cast  off  from  the  body  as  useless, 
excretion  (eks-kre'shun).     The  act  of  throwing  off;   the  discharging  of 

wastes  from  the  body, 
extensors  (eks-ten'sorz).     Muscles  that  serve  to  extend  or  straighten  any 

part  of  the  body,  as  an  arm  or  a  finger;    opposed  to  flexors,  which 

bend  or  contract  muscles. 


fatty  degeneration  (fat'ty  de-jen'er-a'shun).  A  diseased  condition,  in 
which  the  presence  of  too  much  fat  interferes  with  the  working  of 
the  organs. 

fermentation  (fer'men-ta'shun).  A  change  in  a  substance  due  to  the 
action  of  bacteria ;  usually  gas  is  formed,  and  alcohol  also  in  greater 
or  less  quantities. 

fiber  (fTber).  One  of  the  delicate,  thread-like  portions  of  which  the  tis- 
sues of  plants  and  animals  are  in  part  made  up. 

fissures  (fish'urz).  Furrows  or  depressions,  as  in  the  surface  •  of  the 
brain. 


298  GLOSSARY 

flexors  (fleks'orz).     Muscles   which    bend    (flex)    any   part;   opposed  to 

extensors. 
frontal  lobes  (fron'tfll  lobz).     The  round  projecting  parts  of  the  brain  in 

front. 

G 

gall  bladder  (gal  blad'der).     The  sac  in  which  gall  is  stored  up. 

gastric  juice  (gas'trik  jus).     A  thin  watery  fluid  of  an  acid  nature  that 

flows  from  the  walls  of  the  stomach  to  mix  with  the  food  and  aid 

digestion. 

germicide  (jer'mi-sid).     Anything  that  kills  germs. 
glottis  (glot'tis).     The  opening  from  the  pharynx  into  the  larynx  or  into 

the  trachea. 

glycogen  (gli'ko-jen).     Digested  starch  stored  in  the  body. 
gossamer  (gos'sa-mer).     Any  very  thin  gauze-like  fabric;    a  fine,  filmy 

substance  like  cobwebs. 

granule  (gran'ul).     A  little  grain;   a  small  particle;   a  pellet. 
gullet  (gul'let).     The  tube  by  which  food  is  carried  from  the  pharynx 

to  the  stomach  ;   the  esophagus. 


haemoglobin  or  hemoglobin  (hem'o-glo'bm  or  he'mo-glo'bm).     The  coloring 

matter  of  the  red  blood  corpuscles. 
hair  follicle  (har  fol'li-k'l).     A  small  cavity,  or  depression,  at  the  outer 

end  of  a  tiny  tube,  from  which  a  hair  grows. 
hammer  (ham'mer).     One  of  the  three  small  bones  in  the  ear.     It  gets 

its  name  from  its  likeness  to  a  hammer. 
hydrochloric  acid  (hi'dro-klo'rik  as'id).     An  acid  contained  in  the  gastric 

juice. 

incapacitated  (m'ka-pas'i-tat-ed).     Deprived  of  natural  power;   disabled. 
incisors  (m-si'zerz).     The  teeth  in  front  of  the  canines,  or  cuspids.     They 

are  used  especially  for  cutting  food. 
infection  (in-fek'shun).     Disease  caused  by  germs;    also  the  giving  of 

disease  germs  to  a  well  person  by  a  diseased  one. 

inorganic  (in'or-gan'ik).     Without  the  organs  necessary  for  life;   lifeless. 
insoluble   (m-sol'u-b'l).     Incapable  of  being  dissolved  by  a  liquid;   as, 

chalk  is  insoluble  in  water. 


GLOSSARY  299 

insomnia  (in-som'ni-a).     Inability  to  sleep ;  wakefulness;   sleeplessness, 
intestines  (in-tes'tmz).     All  of  the  alimentary  canal  from  the  stomach 

downward, 
iris   (i'ris).     The  movable,  muscular  curtain  lined  with  dark  pigment 

found  in  the  eye. 

jaundice  (jan'dis).     A  disease  in  which  the  eyes  and  skin  turn  yellow; 
it  is  caused  by  an  excess  of  bile  in  the  liver. 


kilogram  (kil'6-gram).     A  measure  of  weight  in  the  metric  system,  equal 
to  about  two  and  one  fifth  pounds  in  our  system. 


lachrymal  gland  (lak'ri-mal  gland).     The  gland  in  which  tears  are  formed. 

lacteals  (lak'te-alz).  The  small  vessels  which  carry  a  milky  fluid  con- 
taining fatty  matter  from  the  small  intestine. 

larynx  (lar'inks).     The  entrance  to  the  windpipe. 

ligaments  (lig'a-ments).  Bands  of  strong  connective  tissue  which  unite 
bones  and  form  joints. 

liver  (liv'er).  The  organ,  lying  near  the  stomach,  which  manufactures 
bile. 

longitudinal  muscles  (lon'ji-tu'di-nal  muscles).  Muscles  that  extend 
lengthwise  with  the  organ  which  they  move. 

lubricated  (lu'bri-ka-ted).  Made  smooth  or  slippery  in  order  to  cause 
movement  without  grating  or  friction. 

lymph  (limf).  The  part  of  the  blood  that  leaks  from  the  blood  vessels. 
It  contains  no  red  blood  corpuscles. 

M 

maltose  (malt'os).  A  crystalline  sugar  sometimes  called  malt  sugar >  de- 
rived from  grains. 

massage  (mas'saj ;  F.  ma'sazh')-  A  rubbing  of  the  body,  done  especially 
as  a  hygienic  or  remedial  measure. 

mastication  (mas'ti-ka'shun),     Chewing;   as,  mastication  of  food. 


300  GLOSSARY 

medulla  (me-dul'la).  An  expansion  of  the  upper  end  of  the  spinal  cord, 
which  controls  such  reflex  acts  as  breathing  and  the  beating  of  the 
heart. 

metabolism  (me-tab'o-liz'm).  The  process  by  which  living  tissues  take 
up  and  change  the  material  that  the  blood  brings  them  for  nourish- 
ment, or  by  which  they  change  their  own  substance  into  waste  mat- 
ter that  can  be  thrown  out  of  the  body. 

microbe  (mi'krobe).  An  organism  so  small  that  it  cannot  be  seen  by  the 
naked  eye. 

microscope  (mi'kro-skop  or  mik'ro-sk5p).  An  instrument  by  which  the 
eye  is  enabled  to  see  organisms  too  small  to  be  seen  without  aid. 

molars  (mo'lerz).  Any  of  the  teeth  back  of  the  incisors  and  canines  i 
the  teeth  used  for  grinding  food. 

morphine  (mor'fin  or  -fen).  A  drug,  made  from  opium,  which  deadens 
pain  and  will  put  a  person  to  sleep,  but  which  is  dangerous. 

mucous  membrane  (mu'kus  mem'bran).  The  thin  layer  of  tissue  lining 
the  passages  and  cavities  of  the  body. 


neuron  (nu'ron).     A  nerve  cell  with  its  branches. 

nicotine  (nik'o-tin  or  -ten).  An  element  found  in  tobacco.  It  is  very 
poisonous. 

nitrogen  (m'tro-jen).  A  chemical  which  may  be  in  the  form  of  gas  or  in 
the  form  of  liquid. 

nitrogenous  foods  (ni-troj'e-nus  foodz).  Foods  which  contain  the  sub- 
stance known  as  nitrogen. 

nucleus  (nu'kle-us).     The  center  of  a  cell. 

nutrient  (nu'tri-ent).     Any  food  which  nourishes. 


olfactory   nerves    (61-fak'to-ry   nervz).     The   nerves   in   the   nose   upon 

which  smell  depends, 
opium  (o'pi-um).     The  juice  of  the  poppy  plant.     It  is  a  narcotic  poison 

which  may  produce  sleep  or  death. 
optic   nerve    (op'tik   nerv).     The  nerve  connecting  eye  and  brain  upon 

which  sight  depends. 


GLOSSARY  301 

organic  (6r-gan'ik).     Having  organs ;   alive. 

osseous  tissue  (os'se-us  tish'u).     Tissue  that  is  like  bone;   hard  tissue, 
oxygen  (oks'i-jen).     An  element  necessary  to  life,  which  the  body  takes 
in  from  the  air. 


palate  (paTat).     The  roof  of  the  mouth. 

pancreas  (pan'kre"-as).     An  organ  near  the  stomach,  in  which  the  pan- 
creatic juice  is  formed  to  aid  in  digestion, 
papillae  (pa-pil'le).     Tiny  mound-like  projections  of  the  skin, 
parasite   (par'a-sit).     A  plant  or  animal  that   lives  upon,  and  gains  its 

nourishment  from,  the  body  of  another  plant  or  animal. 
parietal  lobes  (pa-ri'e-tfll  lobz).     The  round  projecting  parts  of  the  brain 

at  the  sides  of  the  skull. 
pelvis  (peTvis).     That   part  of  the  body  below  the  stomach,  which   is 

made  up  of  the  pelvic  bones. 

pepsin  (pep'sin).     One  of  the  fluids  composing  the  gastric  juice. 
peptone  (pep'ton).     Fluid  which  is  found  in  the  gastric  juice, 
periosteum     (per'i-os'te-um).     The     membrane     of    fibrous     connective 

tissue  that  covers  all  bones  except  at  the  joints. 
peristaltic  movement  (per'i-stal'tik  modv'ment).     A   peculiar  worm-like 

wave  motion  of  the  intestines  which  causes  the  food  to  move  on. 
pestilence  (pes'ti-L?ns).     The  plague,  or  any  terrible  fatal  disease  that 

spreads  easily,  rapidly,  and  widely. 
pharynx    (far'inks).     The    part    of   the    alimentary    canal    between    the 

mouth  and  the  esophagus, 
physique  (fi-zek').     The  physical  build  or  structure  of  a  person;   physical 

appearance, 
plague  (plag).     An  acute  contagious  fever,  incurable  and  terrible  in  its 

attacks  ;  any  disease  that  destroys  many  people  in  a  short  space  of  time, 
plasma  (plaz'ma).     The  fluid  part  of  the  blood  in  which  the  cells  float, 
plumb  line  (plum  Hn).     A  straight  line  between  two  points,  as  between 

the  forehead  and  the  floor. 
posterior  chamber    (pos-te'ri-er  cham'ber).     The  inclosed   space  in  the 

eye  behind  the  lens, 
proteid  (pro'te-id).     One  of  the  elements  present  in  greater  or  less  degree 

in  nearly  all  plants  and  to  a  large  degree  in  animal  tissues  and  organs. 


302  GLOSSARY 

protein  (pro'te-in).  One  of  the  class  of  nutrients  which  furnishes  build- 
ing material  for  the  body. 

ptomaines  (to'ma-inz  or  -enz).  A  class  of  substances  that  grow  in  dead 
matter; '  poisons. 

pulmonary  circulation  (pul'mo-na'ry  ser'ku-la'shun).  The  movement  of 
the  blood  as  it  passes  through  the  heart  and  the  lungs  and  through- 
out the  body. 

pulse  (puls).  The  beating  of  the  heart  or  blood  vessels,  especially  of  the 
arteries  at  the  wrist  and  in  the  temple. 

pupil  (pu'pil).     The  opening  of  the  eye  in  the  center  of  the  iris. 

pus  (pus).     A  collection  of  dead  white  cells  in  the  body. 

putrefaction  (pu'tre-fak'shun).     The  act  of  rotting,  or  decaying. 

putrefy  (pu'tre-fi).     To  decay;   to  rot. 

pylorus  (pi-lo'rus).     The  opening  of  the  stomach  into  the  intestine. 


rennin  (ren'nin).     One  o.  tne  fluids  composing  the  gastric  juice, 
respiration  (res'pi-ra'shun).     The  act  of  breathing. 

retina  (ret'i-na).  The  inner  coat  of  the  eyeball  containing  the  nerve  cells 
and  fibers  necessary  for  sight. 

.     S 

saliva  (sa-li'va).  A  fluid  found  in  the  mouth  and  manufactured  in  the 
salivary  glands;  it  is  necessary  for  the  digestion  of  starch. 

salivary  glands  (sal'i-va-ry  glandz).  Tiny  sacs  in  the  lining  of  the  mouth 
that  produce  the  fluid  called  saliva. 

scavenger  (skav'en-jer).  One  who  cleans,  removes  waste,  makes  condi- 
tions healthful  by  removing  dirt  and  germs. 

sclerotic  (skle-rot'ik).     The  outer  coat  of  the  eye. 

sebaceous  (se-ba'shus).     Composed  of  fat;   containing  fat. 

secrete  (se-kret').  To  extract  from  the  blood  and  make  into  a  new  sub- 
stance ;  as,  the  salivary  glands  secrete  saliva. 

sedentary   (sed'en-ta-ry).     Inactive  physically;    requiring  much  sitting. 

septum  (sep'tum).  A  partition  separating  the  nostrils  or  nasal  cavity 
into  two  parts. 

serum  (se'rum).  The  pale  yellowish  fluid  that  comes  out  from  a  clot 
of  blood. 

spasmodic  (spaz-m5d'fk).     Convulsive;  irregular;  jerky;  uneven. 


GLOSSARY  303 

spirometer  (spi-rom'e-ter).  An  instrument  for  measuring  the  vital  ca- 
pacity of  the  lungs ;  that  is,  the  volume  of  air  which  can  be  expelled 
from  the  chest  after  the  deepest  possible  taking  in  of  breath. 

sputum  (spu'tum).     Saliva;  what  is  expectorated ;   spittle. 

stagnant  (stag'nant).  Not  flowing;  motionless;  impure  from  want  of 
motion. 

sternum  (ster'num).     The  breastbone. 

stimulus  (stim'u-lus).  Something  that  rouses  to  action;  as,  a  stimulus  to 
sight  or  hearing  or  taste. 

stirrup  (ster'rup).  One  of  the  three  small  bones  of  the  ear.  It  takes  its 
name  from  its  shape. 

suspensory  ligament  (sus-pen'so-ry  lig'a-ment),  A  suspended  or  hanging 
band  of  connective  tissue. 

symmetrical  (sim-met'ri-kal).  Having  one  side  like  another;  even; 
regular. 

symmetry  (sim'me-try).  Correct  proportion  or  balance  of  the  parts  of 
the  body. 


tannin  (tan'nin).     A  harmful  acid  found  in  tea. 

temporal  lobes  (tem'po-ral  lobz).  The  round  projecting  parts  of  the  brain 
at  both  sides  of  the  skull. 

theine  (the'm  or  -en).     A  poison  found  in  tea  and  coffee. 

thoracic  duct  (tho-ras'ik  dukt).  The  great  trunk  of  the  lymphatic  ves- 
sels, between  the  intestines  and  the  heart. 

thorax  (tho'raks).  The  part  of  the  trunk  between  the  neck  and  the 
abdomen. 

tissue  (tish'u).  The  fibers  that  go  to  make  up  organs  of  any  sort,  as  the 
heart  or  lungs. 

tonsils  (ton'sils).  Two  organs  placed  on  each  side  of  the  throat.  They 
serve  to  destroy  germs  on  the  way  to  the  lungs. 

toxin  (toks'in).  A  poison;  used  often  in  reference  to  the  poisons  devel- 
oped within  the  body. 

trachea  (tra'ke-a  or  tra-ke'a).     The  windpipe. 

tympanic  membrane  (tim-pan'ik  mem'bran).  The  delicate  skin  in  the 
ear  stretched  across  the  lower  end  of  the  canal.  It  is  commonly  called 
the  drum. 


304  GLOSSARY 


ventricle  (ven'tri-k'l).  One  of  the  cavities  of  the  heart  which  forces  the 
blood  from  the  heart  into  the  arteries. 

vertebrae  (ver'te-bre).  Plural  of  vertebra.  The  small  bones  that  make  up 
the  backbone. 

villi  (vil'li).  Plural  of  villus,  which  is  rarely  used.  The  tiny,  fine,  finger- 
like  projections  which  cover  the  lining  of  the  stomach. 


INDEX 


Abdominal  Breathing,  112. 

Acquired  Reflex  Actions,  1 09-200. 

Action  of  Muscles,  91-92,  168-171. 

Adenoids,  113-114. 

Adulterants,  58-60 ;  shellac  as  an  adulter- 
ant, 60;  how  to  detect,  60. 

Adulteration,  of  foods,  58-59;  of  candy, 
60. 

Air,  fresh,  during  sleep,  115;  amount  needed 
regularly  for  health,  119-120. 

Alcohol,  effect  of,  on  bodily  organs,  9;  on 
blood,  93  ;  on  the  heart,  97-98;  on  air  pas- 
sages and  lungs,  n6;on  kidneys,  129;  on 
sense  of  taste,  234;  enemy  of  the  body. 
240 ;  kills  living  things,  240 ;  experiment 
made  on  Alexis  St.  Martin,  241 ;  stomach 
injured  by,  241 ;  liver  injured  by,  242 ; 
hardens  brain  and  nerve  tissues,  242; 
effect  of,  on  body  defenses,  257. 

Alimentary  Canal,  23. 

Amoeba,  i. 

Animals,  expenders  of  energy,  15;  as  car- 
riers of  contagious  diseases,  267. 

Antitoxins,  251,  262-263. 

Anvil,  227. 

"Appetite  Juice, "45. 

Aqueous  Humor,  211. 

Arteries,  81. 

Astigmatism,  215. 

Attachment,  of  muscles  to  bones,  169 ;  ten- 
dons, 169. 

Auditory  Canal,  226. 

Auricle,  82. 

Auto-intoxication,  37 ;  effect  of,  on  the  eyes, 


Ball-and-Socket  Joints,  155.. 

Bathing,  133. 

Baths,  effect  of  cold,  on  blood,  95-96;    on 

nerves  of  touch,  236;   hot  and  cold,  143- 

144- 
Benzoate  of  Soda,  as  food  preservative,  61. 


Biceps,  experiment  with,  170. 

Bile,  cells  that  form,  7  ;  in  digestion,  32. 

"Bilious"  Condition,  cause  of,  35-36. 

Bitterness,  as  taste  sensation,  234. 

Blood,  71-91 ;  Hunter's  experiments  on 
animals,  71;  as  "carrier"  of  the  body, 
72 ;  red  blood  cells,  73 ;  haemoglobin,  73  ; 
white  blood  cells,  74-75 ;  how  the  body 
is  protected  by  blood  cells,  75-77 ;  how 
a  boil  or  abscess  is  formed,  76 ;  how  a  cut 
heals,  77 ;  the  plasma,  77,  78;  the  circula- 
tion, 79 ;  the  heart,  79-80 ;  size  and  shape 
of  the  heart,  80 ;  valves  of  the  heart,  80 ; 
action  of  the  heart,  80,  81 ;  the  blood 
vessels,  81 ;  arteries,  81 ;  veins,  81 ;  cap- 
illaries, 81 ;  three  systems  of  circulation, 
81,  84;  systematic  circulation,  81 ;  pul- 
monary circulation,  81 ;  portal  circulation, 
84;  the  lymph,  85;  how  circulated,  86- 
87- 

Body,  sources  of  material  for,  13-14;  sym- 
metrical development  of,  161-164;  in 
motion,  167-176;  see  Living  Wonders 
of  the  Body,  Temperature  of  Body. 

Bones,  construction  of,  149-151;  uses  of, 
151-152;  broken,  157,  158. 

Boracic  Acid,  as  food  preservative,  61. 

Brain  and  Nerve  Tissues  Hardened  by  Al- 
cohol, 242. 

Bread,  careless  handling  of,  64 ;  experiments 
made  in  bakeries,  64-65. 

Breathing  Apparatus,  103-110;  lungs,  103- 
104;  windpipe  or  trachea,  104;  larynx, 
104-107;  bronchial  tubes,  104;  bronchi, 
105 ;  bronchioles,  105 ;  air  cells,  105 ; 
pleura,  105 ;  the  nostrils,  106 ;  nasal 
cavity,  106;  pharynx,  106;  tonsils,  107; 
glottis,  107 ;  epiglottis,  108. 

Breathing,  correct,  in;  inspiration,  no; 
expiration,  in;  costal  or  rib,  in;  ab- 
dominal, 112;  through  the  nostrils,  113; 
mouth,  caused  by  adenoids,  113;  as  an 


305 


306 


INDEX 


aid  to  circulation  and  digestion,  115-116; 
exercises,  118-119. 

Capillaries,  81. 

Carbohydrates,  15. 

Carbon  Dioxide,  formed  by  muscular 
work,  172. 

Cardiac  Opening,  28. 

"Carriers"  of  Contagious  Diseases,  263. 

"Catching"  Diseases,  260-270;  danger  of, 
260 ;  smallpox,  260 ;  measles,  260 ;  scarlet 
fever,  260 ;  mumps,  260 ;  whooping  cough, 
260;  quarantine,  260;  making  a  "cul- 
ture" of  a  contagious  disease,  261;  anti- 
toxin, 262-263;  "carriers"  of,  263; 
precautions  to  be  observed  in  quaran- 
tine, 263—269. 

Cells,  i. 

Cell  Colonies  or  Communities,  4. 

Cell  Organs  or  Cell  Groups,  7 ;  meaning  of 
"organism,"  8;  division  of  work,  7. 

Cell  Structures  or  Tissues,  5 ;  adipose  tis- 
sue, 6 ;  connective  tissue,  5 ;  muscular 
tissue,  6;  osseous  tissue,  6;  cartilage 
tissue,  6;  nervous  tissue,  6;  epithelial 
tissue,  6. 

Cellulose,  16. 

Central  Nervous  System,  192. 

Cerebellum,  195. 

Cerebrum,  195. 

Chocolate,  effect  of,  on  nervous  system, 
202. 

Choroid,  210. 

Circulation  of  the  Blood,  79. 

Clothing,  as  protection  against  heat  loss,  144 ; 
proper  and  improper,  145-147. 

Cochlea,  227. 

Coffee,  effect  of,  on  blood,  93 ;  on  kidneys, 
129;  on  nervous  system,  202. 

Cold,  effect  of,  on  blood  vessels,  88. 

Colds,  cause  and  cure,  143. 

Colon,  for  food  residue,  3  5 ;  poisons  formed 
in,  36 ;  effect  of  poison  from,  203. 

Composition  of  Foods,  tables,  289-292. 

Condiments,   effect  of,   on  sense  of  taste, 

234- 

Confusion  of  smell  and  taste,  232—233. 

Contagious  Diseases,  see  "Catching"  Dis- 
eases. 

Cornea,  209. 

Corrective  Exercises,  184-187 ;  how  to  cor- 
rect round  shoulders,  186;  a  flat  chest, 


1 86;  relaxed  abdomen,  187 ;  bent  fingers, 
187 ;  weak  arches,  187. 
Crystalline  Lens,  211. 

Deformities,  how  caused,  161-164;  spinal 
curvature,  163-164. 

Dermis,  130. 

Digestion,  23-43;  alimentary  canal,  23; 
digestive  juices,  24;  mastication,  first 
step  in,  25;  saliva,  work  of,  26-27; 
starch  changed  into  maltose,  26 ;  salivary 
glands,  26;  esophagus,  27;  cardiac  open- 
ing, 28;  pylorus,  28;  stomach,  28^-31; 
gastric  juice,  work  of,  29;  digestive  fer- 
ments, 29-30;  hydrochloric  acid,  work 
of  in,  30—3 1 ;  kneading  the  food,  3 1 ; 
alkali  in  bile,  32;  pancreatic  juice,  33; 
small  intestine  in,  33;  liver,  38;  gall 
bladder,  32;  bile  in,  32,  40;  of  fats,  32; 
the  villi,  work  of,  34;  peristaltic  move- 
ments, 35 ;  large  intestine,  last  food  sta- 
tion, 35 ;  ileoca;cal  valve,  35 ;  colon,  for 
food  residue,  35;  microbes,  work  of,  hi 
intestines,  36-37 ;  poisons  formed  in  colon, 
37 ;  auto-intoxication,  37 ;  work  of  liver, 
22-24;  lacteals,  40;  thoracic  duct,  40; 
making  blood  into  tissue,  41-42;  as  de- 
pendent upon  enjoyment  of  food,  44-45 ; 
temperature  required  for,  46 ;  hindrances 
to,  48-51;  effect  of  mind  on,  51. 

Digestive  Ferments,  29;  pepsin,  29;  ren- 
nin,  29-30. 

Digestive  Juices,  24. 

Disease  Germs,  enemies  of  the  body,  248- 
259;  how  they  spread,  248-249;  how 
they  enter  the  body,  249 ;  how  they  mul- 
tiply, 250;  fevers  caused  by  germ-formed 
poisons,  250;  how  the  body  defends  it- 
self, 251-252;  result  of  weakening  body 
defenses,  251;  how  one  becomes  immune 
to,  252;  guarding  against,  252-253; 
domestic  hygiene,  253 ;  sunlight  as  a 
disinfectant,  254;  personal  hygiene,  254- 
255 ;  how  one  who  has  a  cold  can  protect 
others  from  catching  it,  257;  keeping 
body  defenses  in  good  repair,  257 ;  effect 
of  alcohol  on  body  defenses,  257. 

Domestic  Hygiene,  253. 

Drinking  at  Meals,  46. 

Ear  Drum,  226 ;  how  it  may  be  injured,  23(5. 
Ear,  parts  of,   226-228;    outer  ear,   226; 


INDEX 


307 


auditory  canal,  226;  drum  (tympanic 
membrane),  227;  eustachian  tube,  227; 
the  hammer,  anvil,  and  stirrup,  227; 
cochlea,  228;  membranous  labyrinth,  228; 
care  of,  228-230. 

Eating  for  Health  and  Pleasure,  44-55  J 
Professor  Pavlov,  on  enjoyment  of  food, 
44;  "appetite  juice,"  45;  causes  of  in- 
digestion, 46-51;  bolting  of  food,  46; 
drinking  at  meals,  46;  temperature  re- 
quired for  digestion,  46;  harmful  effect 
of  ice  water,  46 ;  time  to  drink  liquids,  47 ; 
variety  in  food  necessary,  47 ;  simplicity 
in  food,  47 ;  a  "tired"  stomach,  46;  num- 
ber of  meals  each  day,  48;  eating,  just 
before  bedtime,  49-50;  irregularity  in 
time  of  meals,  50;  violent  exercise  just 
before  or  after,  50;  effect  of  mind  on  di- 
gestion, 51-52. 

Elimination  of  Wastes,  126-135;  organs  of 
excretion,  126-133;  intestines,  126;  the 
kidneys  as  organs  of  excretion,  126-128; 
habits. that  injure  the  kidneys,  129;  the 
skin  as  an  organ  of  excretion,  132-133; 
sebaceous  glands,  131 ;  sweat  glands,  132 ; 
bathing  to  remove  waste  matter  from 
skin,  133. 

Emotions,  effect  of,  on  the  heart,  97. 

Enemies  of  the  Body,  see  Alcohol,  Tobacco, 
Disease  Germs. 

Energy,  sources  of,  13-14. 

Epidermis,  130. 

Epithelial  Tissue,  6. 

Esophagus,  27. 

Eustachian  Tube,  227. 

Exercise,  effect  of,  on  the  heart,  98 ;  on  heat 
production,  141-142. 

Expiration,  in. 

Eye,  a  sort  of  camera,  207;  protection  of, 
208-209;  the  lachrymal  gland,  209; 
sclerotic  (outer  coat),  209;  choroid  (middle 
coat),  209;  retina  (inner  coat),  209;  the 
cornea,  209;  iris,  210;  pupil,  210;  crys- 
talline lens,  211 ;  vitreous  humor,  211; 
aqueous  humor, '211;  care  of,  218-222; 
practices  harmful  to,  218-220;  effect  of 
auto-intoxication  on,  222. 

Farsightedness,  214. 
Fat  Cells,  7. 

Fatigue,  death  from,  172-173;  of  one  part 
of  the  body  carried  to  other  parts,  1735 


curing,  173;  after  effects  of,  174;  effect 
of,  on  muscles,  182-184;  effect  of,  on 
nervous  system,  201-202. 

Fats,  15;  digestion  of,  32-33- 

Feeling  and  Thinking,  190-206;  nerve  cells, 
190;  nerve  fibers,  191;  neuron,  191; 
ganglion,  193 ;  sympathetic  nervous  sys- 
tem, 192  ;  central  nervous  system,  192 ; 
how  we  feel  and  think,  193 ;  sensory,  or 
ingoing,  nerves,  194;  motor,  or  outgoing, 
nerves,  194-195;  cerebrum,  195;  cere- 
bellum, 195 ;  the  medulla  and  its  work, 
197-198;  the  spinal  cord  and  its  work, 
199;  reflex  action,  198;  acquired  reflex 
actions,  199;  how  habits  are  formed, 
200-20 1 ;  memory,  201 ;  sleep  necessary 
for  health  of  nervous  system,  202 ;  effect 
of  tea,  coffee,  and  chocolate  on  nervous 
system,  202 ;  effect  of  fatigue  on  nervous 
system,  201-202 ;  effect  of  absorption 
of  colon  wastes  on  nervous  system,  203 ; 
nerve  poisons,  203-204. 

Food,  combustion  of,  12  ;  as  source  of  energy, 
13;  composition  of,  15-18;  carbohydrates, 
15;  cellulose,  16;  fats,  15-17;  proteins, 
15,  17;  salts,  16;  flavoring  substances, 
16;  vitamines,  16;  starch,  16;  phos- 
phorus, 18;  sulphur,  18;  iron,  18;  lime, 
18;  variety  in,  47;  simplicity  in,  47; 
adulteration  of,  58-59;  harmful  color- 
ing matter  in,  59-61 ;  summer  and  win- 
ter diet,  282-285  5  see  Digestion,  Food 
Values. 

Food  Values,  table  of,  18. 

Framework  of  the  Body,  149-166;  con- 
struction of  bones,  149-151;  the  skele- 
ton, 150,  152;  the  periosteum,  151;  uses 
of  bones,  151-152;  the  spinal  column  as 
protection  for  spinal  cord,  153 ;  bones 
held  together  by  ligaments,  153 ;  ver- 
tebrae, 153;  how  jarring  of  the  body  is 
prevented,  154;  the  joints,  154;  im- 
movable joints,  155;  movable  joints, 
155;  ball-and-socket  joints,  155;  hinge 
joints,  156;  gliding  joints,  156;  injuries 
to  bones  and  joints,  156-158;  effect  of 
tobacco  on  development  of  bones,  158; 
keeping  the  body  straight,  160-164;  a 
slouching  body,  160;  erect  posture,  160- 
161 ;  how  deformities  are  caused,  163-164 ; 
spinal  curvature,  163-164;  lime  essential 
to  growth  of  bones,  164. 


308 


INDEX 


Gall  Bladder,  32. 

Ganglion,  191. 

Gastric  Juice,  cells  that  form,  7 ;  work  of,  29. 

Gateways  of  the  Mind,  see  Sight,  Hearing, 

Smell,  Touch,  Taste. 
Gland  Cells,  7 ;    that  lorm   saliva,   7 ;    that 

form  gastric  juice,  7 ;    that  form  bile,  7 ; 

that  form  sweat,  7 ;  that  form  fat,  7. 
Gliding  Joints,  156. 
Glycogen,  38;  as  fuel  for  the  muscles,  172. 

Habit  Formation,  200-201. 

Haemoglobin,  42. 

Hair,  131. 

Hammer,  227. 

Headache  Remedies,  effect  of,  on  the  heart, 
98. 

Healing  of  a  Cut,  77. 

Health  and  Symmetry,  177-189;  muscle 
training  in  daily  tasks,  177 ;  exercising 
in  one's  room,  181-182;  exercise  for 
symmetrical  development,  183-185;  pre- 
venting one-sided  development,  184-185; 
corrective  exercises,  186-187;  how  to 
correct  round  shoulders,  186;  how  to 
correct  a  flat  chest,  186. 

Health  Crusaders,  271-288. 

Health  Rules,  275. 

Hearing,  a  gateway  of  the  mind,  225-231 ; 
how  sound  is  produced,  225;  how  we 
hear,  226;  see  Ear. 

Heart,  79-81 ;  size  and  shape  of,  80 ;  valves 
of,  80-82 ;  action  of,  80-81 ;  the  auricles, 
82  ;  the  ventricles,  82  ;  heart  beat,  rapidity 
of,  87-88 ;  injuring,  96-99 ;  effect  of  ex- 
tremes of  heat  and  cold  on,  96 ;  strong 
emotions  on,  97 ;  excessive  use  of  tobacco 
on,  97 ;  alcohol  on,  97-98 ;  headache 
remedies  on,  98;  lack  of  elimination  on, 
98 ;  severe  exercise  on,  98. 

Heat,  furnished  by  carbohydrates  and  fats, 
18;  effect  of,  on  blood  vessels,  88-89; 
production  of,  137 ;.  effect  of  exercise  on, 
141-142 ;  relation  of  food  to,  142 ;  effect 
on,  of  life  in  heated  homes,  142. 

Hinge  joints,  156. 

Ice  Water,  harmful  effect  of,  46. 

Ileocaecal  Valve,  35. 

Images,  how  formed  and  retained  by  the 

eye,  211-213. 
Immovable  Joints,  155. 


Impure  Blood,  from  wastes  from  colon,  93- 
94- 

Indigestion,  see  Eating  for  Health  and  Pleas- 
ure. 

Ingoing  Nerves,  see  Sensory  Nerves. 

Injuries  to  Bones  and  Joints,  156-158; 
sprains,  157;  how  to  treat  sprains,  157; 
broken  bones,  157-158. 

Inspiration,  no. 

Intestines,  32,  126. 

Involuntary  Muscles,  see  Muscles,  kinds  of. 

Iris,  210. 

Iron,  as  food  element,  18;  value  of,  for 
blood,  94-95;  how  it  may  be  secured,  95. 

Joints,  see  Framework  of  the  Body. 

Kidneys,  work  of,  in  keeping  the  blood 
pure,  93-94,  126-127;  how  they  eliminate 
waste,  127-128;  habits  that  injure,  129; 
over-eating  of  protein  foods,  129;  seden- 
tary habits,  129 ;  effect  of  alcohol,  tobacco, 
tea,  coffee,  and  patent  medicines  on,  129. 

Lack  of  Sleep,  effect  of,  on  blood,  93. 

Lacteals,  40. 

Lactic  Acid,  formed  by  muscular  work,  172. 

Large  Intestine,  35-36. 

Ligaments,  153,  155. 

Lime,  as  food  element,  18;  essential  to 
growth  of  bones,  164;  amount  of,  re- 
quired every  day,  164. 

Liver,  32 ;  as  a  wonderful  laboratory,  38-40 ; 
glycogen  formed  in,  38;  as  food  inspec- 
tor, 39 ;  vitamines  found  in,  39 ;  bile  as 
made  by,  32,  40;  injured  by  alcohol,  242. 

Living  Wonders  of  the  Body,  i-io ;  see  Cell 
Structures  or  Tissues. 

Lungs,  work  of,  in  keeping  blood  pure,  93- 
94;  developing  capacity  of,  116-119; 
"breathing  exercises,"  118;  increasing 
lung  power,  119-121. 

Lymph,  85. 

Lymphatic  Glands,  86 ;  service  of,  86. 

Maintenance  of  Body,  1 1—2  2 ;  how  we  grow, 
11-12;  hunger,  12;  combustion  of  food, 
12;  how.  cells  get  energy,  13;  food  as 
source  of  energy,  13 ;  sources  of  body 
material,  13-16;  sunlight  as  source  of 
energy,  15;  chlorophyll,  15;  plants  as 
food  producers,  15 ;  plants  as  storehouses 


INDEX 


309 


of  energy,  15 ;  animals  as  expenders  of 
energy,  15;  composition  of  foods,  15-19; 
carbohydrates,  15-16,  18;  cellulose,  16; 
fats,  15-16,  18;  proteins,  15,  17;  salts, 
16;  flavoring  substances,  16;  vitamines, 
16;  starch  as  food  element,  16;  sugar, 
17;  phosphorus  as  food  element,  18; 
sulphur  as  food  element,  18;  iron  as  food 
element,  18;  lime  as  food  element,  18; 
table  of  food  values,  18;  uses  of  the  dif- 
ferent foods,  18-20;  nitrogen,  19,  min- 
erals as  building  material,  19;  water,  as 
necessary  to  the  body,  19-20;  oxygen, 
as  necessary  to  life,  20 ;  poisons,  the  oppo- 
site of  food,  20-21. 

Martin,  Alexis  St.,  experiment  made  on,  with 
alcohol,  240—241. 

Mastication,  25-26. 

Meals,  number  of,  each  day,  48-49;  habits 
of  ancient  and  modern  peoples  in  regard 
to,  49;  evils  from  too  frequent,  48;  ir- 
regularity of,  50;  cheerfulness  at  table, 

Si- 

Measles,  a  contagious  disease,  260. 
Meat,  canned,  danger  of  ptomaines  in,  62-63. 
Medulla  and  Its  Work,  197-198. 
Membranous  Labyrinth,  228. 
Memory,  20. 

Microbes,  work  of,  in  intestines,  36-37. 
Monthly    Chart    for    Bodily  Improvement, 

288. 
Mouth  Breathing,  caused  by  adenoids,  113- 

114. 

Movable  Joints,  155-156. 
Mumps,  a  contagious  disease,  260. 
Muscles,    kinds   of,    167;    voluntary,    167; 

involuntary,    167 ;    shapes   and   sizes  of, 

1 68;    how  attached  to  bones,   169-170; 

muscle  tone,  171 ;  effect  of  fatigue  on,  172. 
Muscular  Tissue,  6. 

Nails,  131. 

Nearsightedness,  214. 

Nerve  Cells,  190-191. 

Nerve  Fibers,  190-191. 

Nerve  Poisons,  203-204. 

Neuron,  191. 

Nitrogen,  19. 

Nostrils,  breathing  through,  113. 

Olfactory  Nerves,  232. 
One-celled  Animals,  i,  7. 


One-sided  Development,  prevention  of,  184- 

185. 

Organism,  meaning  of,  7-8. 
Outer  Ear,  226. 

Outgoing  Nerves,  see  Motor  Nerves. 
Oxygen,  20,  103. 

Pain,  sensation,  236;  as  protection  from 
danger,  237. 

Pancreatic  Juice,  33;  in  digestion  of  fats, 
33- 

Papillae,  233-234. 

Patent  Medicines,  effect  of,  on  kidneys,  129. 

Pavlov,  Professor,  experiments  on  diges- 
tion, 29,  44,  51. 

Pepsin,  see  Digestive  Ferments. 

Peristaltic  Movements,  35. 

Personal  Hygiene,  254-257 ;  how  one  who 
has  a  cold  can  protect  others  from  catch- 
ing it,  257  ;  keeping  body  defenses  in  good 
repair,  257. 

Perspiration,  132-133;  insensible,  132; 
sensible,  132. 

Phosphorus,  as  food  element,  18. 

Plants,  as  food  producers,  15;  as  store- 
houses of  energy,  15. 

Plasma,  77-78. 

Poisons,  opposite  of  food,  20-21. 

Portal  Circulation,  84. 

Posture,  erect,  160-164. 

Preservation  of  Food,  in  cold  places,  66; 
in  an  icebox,  66. 

Preservatives,  harmful  in  foods,  61 ;  boracic 
acid,  6 1 ;  benzoate  of  soda,  61 ;  formalin, 
6 1 ;  salicylic  acid,  61 ;  sulphites,  61. 

Protection  of  Body  by  Blood  Cells,  75~77.  ' 

Proteins,  15;  over-eating  of,  129. 

Ptomaines,  63. 

Pure  Food  Law,  62. 

Purification  of  Blood,  108-109. 

Pulmonary  Circulation,  81.  * 

Pupil,  210. 

Pylorus,  28. 

Quarantine,  260 ;  precautions  to  be  observed 
in,  262-265;  letters  should  not  be  sent 
during,  265-266;  playthings  used  during, 
may  carry  disease,  266-267;  animals  not 
kept  in,  may  carry  disease,  267. 

Reflex  Action,  198. 

Rennin,  see  Digestive  Ferments. 


3io 


INDEX 


Retina,  209. 

Rib  Breathing,  in. 

Round  Shoulders,  correction  of,  186. 

Salicylic  Acid  as  Food  Preservative,  61. 
Saliva,  cells  that  form,  3,  15 ;    work  of,  in 

digestion,    15-16;     starch    changed    into 

maltose,  15. 

Salt,  as  taste  sensation,  234. 
Salts,  16. 

Scarlet  Fever,  a  contagious  disease,  260. 
Sclerotic,  209. 
Sebaceous  Glands,  131. 
Sensation  of  Temperature,  236. 
Sensory  Nerves,  194. 
Sight,   a  gateway   of   the   mind,    207-223  ; 

see  Eye. 
Skin,  as  a  protective  covering,  130;    as  an 

organ  of  excretion,  130 ;  the  dermis,  130 ; 

the  epidermis,  130. 

Sleep,  necessary  for  health  of  nervous  sys- 
tem, 202. 

Small  Intestine,  32. 
Smallpox,  a  contagious  disease,  260. 
Smell,  sense    of,   a   gateway   of   the   mind, 

232-233;  olfactory  nerves,  23  2 ;  confusing 

smell  and  taste,  232-233 ;  destroying  sense 

of,  233. 
Sound,  how  produced,  225;   experiment   to 

show  how  it  travels,  225-226. 
Sourness,  as  taste  sensation,  234. 
Speech,  how  produced,  121. 
Spinal    Column,    as    protection   for    spinal 

cord,  152-154. 

Spinal  Cord  and  Its  Work,  199. 
Spinal  Curvature,  163-164. 
Sprains,  157. 

Standards  or  Norms,  278. 
Starch,  as  a  food  element,  16. 
Stirrup,  227. 
Stomach,  28;   injured  by  alcohol,  20,  240- 

241. 

Sugar,  17. 

Sulphites,  as  food  preservatives,  61. 
Sulphur,  as  food  element,  18. 
Sunlight,  as  a  disinfectant,  254. 
Sweat  Cells,  7. 
Sweat  Glands,  132;   work  of,  in  regulating 

body    temperature,     132;     in    removing 

wastes,  132-133. 

Sweetness,  as  taste  sensation,  234. 
Symmetrical  Development  of  the  Body,  161. 


Sympathetic  Nervous  System,  191-192. 
Systemic  Circulation,  81. 

Taste,  a  gateway  of  the  mind,  233-235; 
papillae,  233-234;  sweetness  as  taste 
sensation,  234;  sourness  as  taste  sen- 
sation, 234;  saltness  as  taste  sensation, 
234;  bitterness  as  taste  sensation,  234; 
effect  of  condiments,  such  as  mustard  and 
pepper,  on,  234 ;  effect  of  alcohol  on,  234 ; 
in  relation  to  hunger,  234-235. 
Tea,  effect  of,  on  blood,  93 ;  on  kidneys, 

129;  on  nervous  system,  202. 
Teeth,  temporary,  25 ;  permanent,  25-26. 
Temperature  of  Body,  how  regulated,  136- 
148;   proper,  136;  how  heat  is  produced, 
137;  how  regulated,  137-143 ;  "shivering," 
138;  work  of  the  sweat  glands,  139-140; 
danger  in  variation  of,  141 ;  what  happens 
in  a  fever,  141 ;   the  treatment  of  fevers, 
141 ;  effect  of  exercise  on  heat  production, 
141-142 ;   relation  of  food  to  heat  produc- 
tion,  142 ;    effect  on  heat  production  of 
life  in  heated  homes,  142 ;  healthful  room 
temperature,  143;   colds,  their  cause  and 
cure,  143 ;  clothing,  see  Clothing. 
Temperature  of  Living  Rooms,  142-143. 
Tendons,  169. 

Thinking  and  Feeling,  see  Feeling  and  Think- 
ing. 

Thoracic  Duct,  40. 

Tissues,  see  Cell  Structures  or  Tissues. 
Tobacco,    effect   of,    on   bodily   organs,   9; 
excessive  use  of,  on  the  heart,  95 ;   on  res- 
piratory passages  in  the  lungs,   116;    on 
kidneys,  129;  on  development  of  bones, 
158;   an  enemy  of  the  body,    244-245; 
experiments  made  in  France  to  determine 
the  effect  of,  on  students,  244 ;  Dr.  Seaver's 
testimony,  244 ;  testimony  of  school,  col- 
lege, and  military  examinations,  244-245. 
Touch,   a  gateway  of  the  mind,    235-237; 
Helen  Keller's  sense  of,  236;   temperature 
sensation,    236;    effect  of  cold  bath  on 
nerves  of,  236 ;  sensation  of  pain,  236. 
Toxins,  250,  262. 
Tympanic  Membrane,  227. 

Veins,  81. 

Ventilation,  of  lungs,  109-111;    inspiration, 

no;  expiration,  110— in. 
Ventricle,  82. 


INDEX 


Vertebrae,  153. 

Villi,  work  of,  33~34- 

Vitamines,  9 ;  as  found  in  liver,  39 :  sources 

of,  39- 

Vitreous  Humor,  211. 
Vocal  Cords,  121-122. 
Voice,  121-123;  how  produced,  121;  how 

to  use,  122-123  J  effect  of  smoking  on,  122. 
Voluntary  Muscles,  see  Muscles,  kinds  of. 


Wastes,  elimination  of,  see  Elimination  oi: 

Wastes. 

Water,  as  necessary  to  the  body,  19-20. 
Weight,  right,  for  boys,  279;   for  girls,  280. 
Weston,  Edward  Pay  son,  walking  feat,  180. 
Whooping  cough,  a  contagious  disease,  260. 
Wonders  of  the  Body,  see  Living   Wonders 

of  the  Body. 
Work  Done  as  Exercise,  180-182. 


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